Production method of pigment-dispersing resin

ABSTRACT

This invention provides a method for producing a pigment-dispersing resin which contains divalent group(s) represented by a general formula (I): 
     
       
         
         
             
             
         
       
         
         
           
             (in which R 1  stands for C 1-10  alkylene group, m is an integer of 1-30, and the m recurring units, 
           
         
       
    
     
       
         
         
             
             
         
       
         
         
           
              may be the same or different),
 
phosphoric acid group(s) and/or sulfonic acid group(s), characterized by copolymerizing a polymerizable unsaturated monomeric mixture in a reaction solvent containing at least 30 mass %, based on the total mass of the reaction solvent, of an organic solvent having no hydroxyl group and having a solubility in 20° C. water of at least 100 mass %.

TECHNICAL FIELD

This invention relates to a novel production method ofpigment-dispersing resin.

BACKGROUND ART

Organic pigment and/or inorganic pigment are widely used in paint, inkand the like in general, for such purposes as favorable appearance,light-shading, rust-proofing and the like. When these pigments are usedin paint, however, in occasions the pigments fail to be uniformlydispersed in the paint to invite inferior appearance or water resistanceof the resulting coating film of the paint, which has been a problemrequiring a solution.

For example, JP Hei 6 (1994)-211944A discloses that a pigment-dispersingresin formed of a copolymer (A) of (meth)acrylate having C₁₋₄ alkylgroup, (meth)acrylate having C₆₋₃₀ alkyl group and polymerizable monomerhaving a specific structure, excels in pigment-dispersing ability ofvarious pigments and exhibits good compatibility with various resinsused for paints, while being free of such problem as weatherability.However, when the pigment-dispersing resin is used in paint, coatingfilm formed therefrom may show inferior water resistance.

JP 2001-2736A discloses that the use of a pigment-dispersing acrylicresin having a weight-average molecular weight within a range of10,000-100,000, which is obtained by copolymerization of a monomericmixture comprising a polymerizable unsaturated monomer containing atleast one of hydrophilic functional group selected from amino group,quaternary ammonium salt group and sulfonic acid group;hydroxyl-containing polymerizable unsaturated monomer; (meth)acrylicacid ester monomer of a specific structure having C₈₋₂₄ branched alkylgroup; and other polymerizable unsaturated monomer can provide apigment-dispersing paste composition of which pigment-dispersibility,let down stability and the like are drastically improved. When thepigment-dispersing resin is used in paint, however, resulting coatingfilm may exhibit inferior water resistance.

DISCLOSURE OF THE INVENTION

The object of the present invention is to provide a pigment-dispersingresin which is capable of forming coating film having excellentappearance and water resistance.

We have engaged in concentrative studies with the view to accomplish theabove object, to now discover that a pigment-dispersing resin capable offorming coating film having excellent appearance and water resistancecould be obtained by copolymerizing a mixture of specific polymerizableunsaturated monomers in a specific reaction solvent, and completed thepresent invention.

Thus, the present invention provides a production method of apigment-dispersing resin (A) containing divalent group(s) represented bythe following general formula (I):

-   -   (in which R₁ stands for C₁₋₁₀ alkylene group, m is an integer of        1-30, and the m recurring units,

-   -    may be the same or different),        phosphoric acid group(s) and/or sulfonic acid group(s),        characterized by copolymerizing a polymerizable unsaturated        monomeric mixture (a) which is selected from the following        polymerizable unsaturated monomeric mixtures (a-1) to (a-4):

polymerizable unsaturated monomeric mixture (a-1): a mixture ofpolymerizable unsaturated monomer(s) (m-1) having a divalent grouprepresented by the above general formula (I), phosphoric acidgroup-containing polymerizable unsaturated monomer(s) (m-2), andpolymerizable unsaturated monomer(s) (m-3) other than thosepolymerizable unsaturated monomers (m-1) and (m-2);

polymerizable unsaturated monomeric mixture (a-2): a mixture ofpolymerizable unsaturated monomer(s) (m-1) having a divalent grouprepresented by the above general formula (I), sulfonic acidgroup-containing polymerizable unsaturated monomer(s) (m-4), andpolymerizable unsaturated monomer(s) (m-5) other than thosepolymerizable unsaturated monomers (m-1) and (m-4);

polymerizable unsaturated monomeric mixture (a-3): a mixture ofpolymerizable unsaturated monomer(s) (m-6) having the divalent grouprepresented by the above general formula (I) and phosphoric acid group,and polymerizable unsaturated monomer(s) (m-7) other than thepolymerizable unsaturated monomer(s) (m-6); and

polymerizable unsaturated monomeric mixture (a-4): a mixture ofpolymerizable unsaturated monomer(s) (m-8) having the divalent grouprepresented by the above general formula (I) and sulfonic acid group,and polymerizable unsaturated monomer(s) (m-9) other than thepolymerizable unsaturated monomer(s) (m-8); in a reaction solvent (b)which comprises at least 30 mass %, based on the total mass of thereaction solvent, of an organic solvent (b-1) having no hydroxyl groupand having a solubility in 20° C. water of at least 100 mass %.

The pigment-dispersing resin (A) of the present invention can provide,when it is used in pigment-containing paint, paint which forms coatingfilm having excellent appearance and water resistance.

Hereinafter the production method of the pigment-dispersing resin (A) ofthe invention is explained in further details.

Polymerizable Unsaturated Monomeric Mixture (a-1)

Polymerizable unsaturated monomeric mixture (a-1) is a mixture of thefollowing polymerizable unsaturated monomer (m-1), phosphoric acidgroup-containing polymerizable unsaturated monomer (m-2), andpolymerizable unsaturated monomer (m-3) other than those polymerizableunsaturated monomers (m-1) and (m-2).

Polymerizable Unsaturated Monomer (m-1)

Polymerizable unsaturated monomer (m-1) is a polymerizable unsaturatedmonomer containing a divalent group represented by the following generalformula (I):

-   -   (in which R₁ stands for C₁₋₁₀ alkylene group, m is an integer of        1-30, and the m recurring units,

-   -    may be the same or different)        which can be synthesized by, for example, ring-opening addition        of cyclic ester compound to hydroxyl group of        hydroxyl-containing unsaturated monomer such as        hydroxyl-containing (meth)acrylates, hydroxyl-containing        (meth)acrylamides, by the means known per se.

Examples of above hydroxyl-containing (meth)acrylates includehydroxyalkyl (meth)acrylate such as 2-hydroxyethyl (meth)acrylate and 2-or 3-hydroxylpropyl (meth)acrylate; and examples of hydroxyl-containing(meth)acrylamides include hydroxyalkyl (meth)acrylamide such as2-hydroxyethyl (meth)acrylamide and 2- or 3-hydroxypropyl(meth)acrylamide.

As examples of the cyclic ester compound, C₃₋₁₁ lactones such asβ-propiolactone, dimethylpropiolactone, γ-butyrolactone,γ-valerolactone, δ-valerolactone, γ-caprolactone, δ-caprolactone,ε-caprolactone, γ-caprylolactone and δ-laurolactone can be named, whichcan be used each alone or in combination of two or more. Use ofε-caprolactone is particularly preferred.

As the polymerizable unsaturated monomer (m-1), such polymerizableunsaturated monomers as those obtained by ring-opening addition of, forexample, ε-caprolactone to 2-hydroxyethyl (meth)acrylate or2-hydroxyethyl (meth)acrylamide, can also be used. It is particularlypreferred to use a polymerizable unsaturated monomer obtained byring-opening addition of ε-caprolactone to 2-hydroxyethyl(meth)acrylate. Incidentally, in the present specification“(meth)acrylate” means “acrylate or methacrylate”, “(meth)acrylic acid”means “acrylic acid or methacrylic acid”, “(meth)acryloyl” means“acryloyl or methacryloyl”, and “(meth)acrylamide” means “acrylamide ormethacrylamide”.

As the polymerizable unsaturated monomer (m-1), those available on themarket may be used, for example, PLACCEL FM1 (1 mol-ε-caprolactone-added2-hydroxyethyl methacrylate), PLACCEL FM-2 (2-mol-ε-caprolactone-added2-hydroxyethyl methacrylate), PLACCEL FM-3 (3-mol-ε-caprolactone-added2-hydroxyethyl methacrylate), PLACCEL FM-5 (5-mol-ε-caprolactone-added2-hydroxyethyl methacrylate), PLACCEL FA1 (1 mol-ε-caprolactone-added2-hydroxyethyl acrylate), PLACCEL FA-2 (2 mol-ε-caprolactone-added2-hydroxyethyl acrylate), PLACCEL FA-3 (3 mol-ε-caprolactone-added2-hydroxyethyl acrylate), PLACCEL FA5 (5 mol-ε-caprolactone-added2-hydroxyethyl acrylate), PLACCEL FA10 (10 mol-ε-caprolactone-added2-hydroxyethyl acrylate) and the like.

Above polymerizable unsaturated monomers (m-1) can be used either aloneor in combination of two or more.

Phosphoric Acid Group-containing, Polymerizable Unsaturated Monomer(m-2)

Phosphoric acid group-containing, polymerizable unsaturated monomer(m-2) is a compound which contains at least one each of the phosphoricacid group represented by the following general formula (II):

-   -   (in which R₂ stands for hydrogen atom or a C₁₋₂₀, in particular,        C₁₋₈, hydrocarbon group; preferably hydrogen atom)        and polymerizable unsaturated bond, per molecule.

As the C₁₋₂₀ hydrocarbon groups, for example, straight or branched chainalkyl groups such as butyl, isobutyl, sec-butyl, tert-butyl, pentyl,isopentyl, hexyl, octyl, 2-ethylhexyl, decyl and isodecyl; and phenylgroups can be named.

Examples of the phosphoric acid group-containing, polymerizableunsaturated monomer (m-2) include acid phosphoxyalkyl (meth)acrylatesuch as acid phosphoxyethyl (meth)acrylate, acid phosphoxypropyl(meth)acrylate, acid phosphoxybutyl (meth)acrylate, acid phosphoxyhexyl(meth)acrylate and acid phosphoxydecyl (meth)acrylate; acidphosphoxypolyoxyalkylene glycol mono(meth)acrylate such as acidphosphoxypolyoxyethylene glycol mono(meth)acrylate and acidphosphoxypolyoxypropylene glycol mono(meth)acrylate; polymerizableunsaturated monomers obtained by adding glycidyl (meth)acrylate tomonoalkylphosphoric acid such as monobutylphosphoric acid,monodecylphosphoric acid, monolaurylphosphoric acid andmonosterarylphosphoric acid; and polymerizable unsaturated monomersobtained by adding glycidyl (meth)acrylate to benzylphosphoric acid.

As the polymerizable unsaturated monomer (m-2), those available on themarket can be used, for example, KAYAMER PM-2 of Nippon Kayaku Co.,Ltd.; Light Ester P-1M of Kyoeisha Chemical Co., Ltd.; Phosmer M,Phosmer CL, Phosmer PE and Phosmer PP of Uni-Chemical Co., Ltd.

The above polymerizable unsaturated monomers (m-2) may be used alone orin combination of two or more.

Polymerizable Unsaturated Monomer (m-3) other than the PolymerizableUnsaturated Monomers (m-1) and (m-2)

Polymerizable unsaturated monomer (m-3) include polymerizableunsaturated monomers other than the above polymerizable unsaturatedmonomer (m-1) and phosphoric acid group-containing, polymerizableunsaturated monomer (m-2), examples of which are: alkyl or cycloalkyl(meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate,n-propyl (meth)acrylate, i-propyl (meth)acrylate, n-butyl(meth)acrylate, i-butyl (meth)acrylate, tert-butyl (meth)acrylate,n-hexyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl(meth)acrylate, nonyl (meth)acrylate, tridecyl (meth)acrylate, lauryl(meth)acrylate, stearyl (meth)acrylate, “isostearyl acrylate”(tradename, Osaka Organic Chemical Industry Ltd.), cyclohexyl(meth)acrylate, methylcyclohexyl (meth)acrylate, t-butylcyclohexyl(meth)acrylate, cyclododecyl (meth)acrylate and tricyclodecanyl(meth)acrylate; polymerizable unsaturated monomers having isobornylgroup, such as isobornyl (meth)acrylate; polymerizable unsaturatedmonomers having adamantyl group, such as adamantyl (meth)acrylate;polymerizable unsaturated monomers having tricyclodecanyl group, such astricyclodecanyl (meth)acrylate; vinyl aromatic compounds such asstyrene, α-methylstyrene and vinyltoluene; polymerizable unsaturatedmonomers having alkoxysilyl group, such as vinyltrimethoxysilane,vinyltriethoxysilane, vinyltris(2-methoxyethoxy)silane,γ-(meth)acryloyloxypropyltrimethoxysilane andγ-(meth)acryloyloxypropyltriethoxysilane; perfluoroalkyl (meth)acrylatessuch as perfluorobutylethyl (meth)acrylate and perfluorooctylethyl(meth)acrylate; polymerizable unsaturated monomers having fluorinatedalkyl group such as fluoroolefin; polymerizable unsaturated monomershaving photo-polymerizable functional group like maleimido group; vinylcompounds such as N-vinylpyrrolidone, ethylene, butadiene, chloroprene,vinyl propionate and vinyl acetate; monoesterified products of(meth)acrylic acid with C₂₋₈ dihydric alcohols such as 2-hydroxyethyl(meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl(meth)acrylate and 4-hydroxybutyl (meth)acrylate; hydroxyl-containingpolymerizable unsaturated monomers such as N-hydroxymethyl(meth)acrylamide, allyl alcohol and (meth)acrylate havinghydroxyl-terminated polyoxyethylene chain; carboxyl-containingpolymerizable unsaturated monomers such as (meth)acrylic acid, maleicacid, crotonic acid and β-carboxyethyl acrylate; nitrogen-containingpolymerizable unsaturated monomers such as (meth)acrylonitrile,(meth)acrylamide, N,N-dimethylaminoethyl (meth)acrylate,N,N-dimethylaminopropyl (meth)acrylamide and addition products ofglycidyl (meth)acrylate with amines; polymerizable unsaturated monomershaving at least two polymerizable unsaturated groups per molecule, suchas allyl (meth)acrylate and 1,6-hexanediol di(meth)acrylate;epoxy-containing polymerizable unsaturated monomers such as glycidyl(meth)acrylate, β-methylglycidyl (meth)acrylate,3,4-epoxycyclohexylmethyl (meth)acrylate, 3,4-epoxycyclohexylethyl(meth)acrylate, 3,4-epoxycyclohexylpropyl (meth)acrylate andallylglycidyl ether; (meth)acrylates having alkoxy-terminatedpolyoxyethylene chain; sulfonic acid group-containing polymerizableunsaturated monomers such as 2-acrylamido-2-methylpropanesulfonic acid,2-sulfoethyl (meth)acrylate, allylsulfonic acid, 4-styrenesulfonic acid,and sodium salts or ammonium salts of the foregoing; polymerizableunsaturated monomers having UV absorbing functional group, such as2-hydroxy-4-(3-methacryloyloxy-2-hydroxypropoxy)benzophenone,2-hydroxy-4-(3-acryloyloxy-2-hydroxypropoxy)benzophenone,2,2′-dihydroxy-4-(3-methacryloyloxy-2-hydroxypropoxy)benzophenone,2,2′-dihydroxy-4-(3-acryloyloxy-2-hydroxypropoxy)benzophenone and2-(2′-hydroxy-5′-methacryloyloxyethylphenyl)-2H-benzotriazole; UV-stablepolymerizable unsaturated monomers such as4-(meth)acryloyloxy-1,2,2,6,6-pentamethylpiperidine,4-(meth)acryloyloxy-2,2,6,6-tetramethylpiperidine,4-cyano-4-(meth)acryloylamino-2,2,6,6-tetramethylpiperidine1-(meth)acryloyl-4-(meth)acryloylamino-2,2,6,6-tetramethylpiperidine,1-(meth)acryloyl-4-cyano-4-(meth)acryloylamino-2,2,6,6-tetramethylpiperidine,4-crotonoyloxy-2,2,6,6-tetramethylpiperidine,4-crotonoylamino-2,2,6,6-tetramethylpiperidine and1-crotonoyl-4-crotonoyloxy-2,2,6,6-tetramethylpiperidine; andcarbonyl-containing polymerizable unsaturated monomer compounds such asacrolein, diacetoneacrylamide, diacetonmethacrylamide, acetoacetoxyethylmethacrylate, formylstyrol and C₄₋₇ vinylalkylketones (e.g., vinylmethyl ketone, vinyl ethyl ketone, vinyl butyl ketone). These can beused either alone or in combination of two or more.

It is preferred for the polymerizable unsaturated monomer (m-3), fromthe viewpoint of water resistance of the resulting coating film, tocontain at least one of the polymerizable unsaturated monomer selectedfrom the group consisting of above vinyl aromatic compounds,polymerizable unsaturated monomers having C₆₋₁₈ alkyl groups andpolymerizable unsaturated monomers having C₆₋₁₈ cycloalkyl groups, amongwhich styrene being particularly preferred.

As examples of the polymerizable unsaturated monomers having C₆₋₁₈ alkylgroups, n-hexyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl(meth)acrylate, nonyl (meth)acrylate, tridecyl (meth)acrylate, lauryl(meth)acrylate, stearyl (meth)acrylate and “isostearyl acrylate”(tradename, Osaka Organic Chemical Industry Ltd.) can be named, whichmay be used either alone or in combination of two or more. Of these, useof polymerizable unsaturated monomers having C₈₋₁₃ alkyl groups, inparticular, 2-ethylhexyl (meth)acrylate and/or lauryl (meth)acrylate, ispreferred.

As examples of the polymerizable unsaturated monomers having C₆₋₁₈cycloalkyl groups, cyclohexyl (meth)acrylate, methylcyclohexyl(meth)acrylate, t-butylcyclohexyl (meth)acrylate, cyclododecyl(meth)acrylate, isobornyl (meth)acrylate, adamantyl (meth)acrylate andtricyclodecanyl (meth)acrylate can be named, which may be used eitheralone or in combination of two or more. Of these, use of polymerizableunsaturated monomers having C₈₋₁₃ cycloalkyl groups, in particular,cyclohexyl (meth)acrylate, is preferred.

Where the polymerizable unsaturated monomer (m-3) contains at least oneof the polymerizable unsaturated monomer selected from the groupconsisting of above vinyl aromatic compounds, polymerizable unsaturatedmonomers having C₆₋₁₈ alkyl groups and polymerizable unsaturatedmonomers having C₆₋₁₈ cycloalkyl groups, the combined use amount of thevinyl aromatic compound, polymerizable unsaturated monomer having C₆₋₁₈alkyl group and polymerizable unsaturated monomer having C₆₋₁₈cycloalkyl group is preferably within a range of generally 1-96 mass %,in particular, 10-70 mass %, inter alia, 20-60 mass %, based on thetotal amount of the polymerizable unsaturated monomers (m-1) to (m-3).

Also where the polymerizable unsaturated monomer (m-3) contains styrene,the use amount of styrene is preferably within a range of generally 5-70mass %, in particular, 10-60 mass %, inter alia, 15-50 mass %, based onthe total amount of the polymerizable unsaturated monomers (m-1) to(m-3).

While the mixing ratios of those polymerizable unsaturated monomers(m-1) to (m-3) in the polymerizable unsaturated monomeric mixture (a-1)are not strictly limited, generally they can be within the followingranges, based on the total amount of the polymerizable unsaturatedmonomers (m-1) to (m-3):

-   polymerizable unsaturated monomer (m-1):    -   2-90 mass %, preferably 5-70 mass %, inter alia, 10-60 mass %,-   polymerizable unsaturated monomer (m-2):    -   2-90 mass %, preferably 5-80 mass %, inter alia, 10-70 mass %,-   polymerizable unsaturated monomer (m-3):    -   1-96 mass %, preferably 10-90 mass %, inter alia, 20-80 mass %,        Polymerizable Unsaturated Monomeric Mixture (a-2)

Polymerizable unsaturated monomeric mixture (a-2) is a mixture ofaforesaid polymerizable unsaturated monomer (m-1), sulfonic acidgroup-containing polymerizable unsaturated monomer (m-4), andpolymerizable unsaturated monomer (m-5) other than the polymerizableunsaturated monomers (m-1) and (m-4).

Sulfonic Acid Group-containing Polymerizable Unsaturated Monomer (m-4)

Sulfonic acid group-containing polymerizable unsaturated monomer (m-4)is a compound having at least one each of sulfonic acid group andpolymerizable unsaturated bond per molecule, examples of which including2-acrylamido-2-methylpropanesulfonic acid and 2-sulfoethyl(meth)acrylate. These monomers can be used either alone or incombination of two or more.

Polymerizable Unsaturated Monomer (m-5) other than the PolymerizableUnsaturated Monomers (m-1) and (m-4)

Polymerizable unsaturated monomers (m-5) are polymerizable unsaturatedmonomers other than the polymerizable unsaturated monomers (m-1) andsulfonic acid group-containing polymerizable unsaturated monomers (m-4),examples of which including: alkyl or cycloalkyl (meth)acrylate such asmethyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate,i-propyl (meth)acrylate, n-butyl (meth)acrylate, i-butyl (meth)acrylate,tert-butyl (meth)acrylate, n-hexyl (meth)acrylate, n-octyl(meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate,tridecyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate,“isostearyl acrylate” (tradename, Osaka Organic Chemical Industry Ltd.),cyclohexyl (meth)acrylate, methylcyclohexyl (meth)acrylate,t-butylcyclohexyl (meth)acrylate, cyclododecyl (meth)acrylate andtricyclodecanyl (meth)acrylate; polymerizable unsaturated monomershaving isobornyl group, such as isobornyl (meth)acrylate; polymerizableunsaturated monomers having adamantyl group, such as adamantyl(meth)acrylate; polymerizable unsaturated monomers havingtricyclodecanyl group, such as tricyclodecanyl (meth)acrylate; vinylaromatic compounds such as styrene, α-methylstyrene and vinyltoluene;polymerizable unsaturated monomers having alkoxysilyl group, such asvinyltrimethoxysilane, vinyltriethoxysilane,vinyltris(2-methoxyethoxy)silane,γ-(meth)acryloyloxypropyltrimethoxysilane andγ-(meth)acryloyloxypropyltriethoxysilane; perfluoroalkyl (meth)acrylatessuch as perfluorobutylethyl (meth)acrylate and perfluorooctylethyl(meth)acrylate; polymerizable unsaturated monomers having fluorinatedalkyl group such as fluoroolefin; polymerizable unsaturated monomershaving photo-polymerizable functional group like maleimido group; vinylcompounds such as N-vinylpyrrolidone, ethylene, butadiene, chloroprene,vinyl propionate and vinyl acetate; monoesterified products of(meth)acrylic acid with C₂₋₈ dihydric alcohols such as 2-hydroxyethyl(meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl(meth)acrylate and 4-hydroxybutyl (meth)acrylate; hydroxyl-containingpolymerizable unsaturated monomers such as N-hydroxymethyl(meth)acrylamide, allyl alcohol and (meth)acrylate havinghydroxyl-terminated polyoxyethylene chain; carboxyl-containingpolymerizable unsaturated monomers such as (meth)acrylic acid, maleicacid, crotonic acid and β-carboxyethyl acrylate; nitrogen-containingpolymerizable unsaturated monomers such as (meth)acrylonitrile,(meth)acrylamide, N,N-dimethylaminoethyl (meth)acrylate,N,N-dimethylaminopropyl (meth)acrylamide and addition products ofglycidyl (meth)acrylate with amines; polymerizable unsaturated monomershaving at least two polymerizable unsaturated groups per molecule, suchas allyl (meth)acrylate and 1,6-hexanediol di(meth)acrylate,epoxy-containing polymerizable unsaturated monomers such as glycidyl(meth)acrylate, β-methylglycidyl (meth)acrylate,3,4-epoxycyclohexylmethyl (meth)acrylate, 3,4-epoxycyclohexylethyl(meth)acrylate, 3,4-epoxycyclohexylpropyl (meth)acrylate andallylglycidyl ether; (meth)acrylates having alkoxy-terminatedpolyoxyethylene chain; phosphoric acid group-containing polymerizableunsaturated monomers such as acid phosphoxyethyl (meth)acrylate, acidphosphoxypolyoxyethylene glycol mono(meth)acrylate and acidphosphoxypolyoxypropylene glycol mono(meth)acrylate; polymerizableunsaturated monomers having UV absorbing functional group, such as2-hydroxy-4-(3-methacryloyloxy-2-hydroxypropoxy)benzophenone,2-hydroxy-4-(3-acryloyloxy-2-hydroxypropoxy)benzophenone,2,2′-dihydroxy-4-(3-methacryloyloxy-2-hydroxypropoxy)benzophenone,2,2′-dihydroxy-4-(3-acryloyloxy-2-hydroxypropoxy)benzophenone and2-(2′-hydroxy-5′-methacryloyloxyethylphenyl)-2H-benzotriazole; UV-stablepolymerizable unsaturated monomers such as4-(meth)acryloyloxy-1,2,2,6,6-pentamethylpiperidine,4-(meth)acryloyloxy-2,2,6,6-tetramethylpiperidine,4-cyano-4-(meth)acryloylamino-2,2,6,6-tetramethylpiperidine,1-(meth)acryloyl-4-(meth)acryloylamino-2,2,6,6-tetramethylpiperidine1-(meth)acryloyl-4-cyano-4-(meth)acryloylamino-2,2,6,6-tetramethylpiperidine,4-crotonoyloxy-2,2,6,6-tetramethylpiperidine,4-crotonoylamino-2,2,6,6-tetramethylpiperidine and1-crotonoyl-4-crotonoyloxy-2,2,6,6-tetramethylpiperidine; andcarbonyl-containing polymerizable unsaturated monomer compounds such asacrolein, diacetoneacrylamide, diacetonmethacrylamide, acetoacetoxyethylmethacrylate, formylstyrol and C₄₋₇ vinylalkylketones (e.g., vinylmethyl ketone, vinyl ethyl ketone, vinyl butyl ketone). These can beused either alone or in combination of two or more.

It is particularly preferred for the polymerizable unsaturated monomer(m-5), from the viewpoint of water resistance of the resulting coatingfilm, to contain at least one of the polymerizable unsaturated monomerselected from the group consisting of above vinyl aromatic compounds,polymerizable unsaturated monomers having C₆₋₁₈ alkyl groups andpolymerizable unsaturated monomers having C₆₋₁₈ cycloalkyl groups, amongwhich styrene being particularly preferred.

As examples of the polymerizable unsaturated monomers having C₆₋₁₈ alkylgroups, n-hexyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl(meth)acrylate, nonyl (meth)acrylate, tridecyl (meth)acrylate, lauryl(meth)acrylate, stearyl (meth)acrylate and “isostearyl acrylate”(tradename, Osaka Organic Chemical Industry Ltd.) can be named, whichmay be used either alone or in combination of two or more. Of these, useof polymerizable unsaturated monomers having C₈₋₁₃ alkyl groups, inparticular, 2-ethylhexyl (meth)acrylate and/or lauryl (meth)acrylate, ispreferred.

As examples of the polymerizable unsaturated monomers having C₆₋₁₈cycloalkyl groups, cyclohexyl (meth)acrylate, methylcyclohexyl(meth)acrylate, t-butylcyclohexyl (meth)acrylate, cyclododecyl(meth)acrylate, isobornyl (meth)acrylate, adamantyl (meth)acrylate andtricyclodecanyl (meth)acrylate can be named, which may be used eitheralone or in combination of two or more. Of these, use of polymerizableunsaturated monomers having C₈₋₁₃ cycloalkyl groups, in particular,cyclohexyl (meth)acrylate, is preferred.

Where the polymerizable unsaturated monomer (m-5) contains at least oneof the polymerizable unsaturated monomer selected from the groupconsisting of above vinyl aromatic compounds, polymerizable unsaturatedmonomers having C₆₋₁₈ alkyl groups and polymerizable unsaturatedmonomers having C₆₋₁₈ cycloalkyl groups, the combined use amount of thevinyl aromatic compound, polymerizable unsaturated monomer having C₆₋₁₈alkyl group and polymerizable unsaturated monomer having C₆₋₁₈cycloalkyl group is preferably within a range of generally 1-96 mass %,in particular, 10-70 mass %, inter alia, 20-60 mass %, based on thetotal amount of the polymerizable unsaturated monomers (m-1), (m-4) and(m-5).

Also where the polymerizable unsaturated monomer (m-5) contains styrene,the use amount of styrene is preferably within a range of generally 5-70mass %, in particular, 10-60 mass %, inter alia, 15-50 mass %, based onthe total amount of the polymerizable unsaturated monomers (m-1), (m-4)and (m-5).

While the mixing ratios of those polymerizable unsaturated monomers(m-1), (m-4) and (m-5) in the polymerizable unsaturated monomericmixture (a-2) are not strictly limited, generally they can be within thefollowing ranges, based on the total amount of the polymerizableunsaturated monomers (m-1), (m-4) and (m-5):

-   polymerizable unsaturated monomer (m-1):    -   2-90 mass %, preferably 5-70 mass %, inter alia, 10-60 mass %,-   polymerizable unsaturated monomer (m-4):    -   2-60 mass %, preferably 5-50 mass %, inter alia, 10-40 mass %,-   polymerizable unsaturated monomer (m-5):    -   1-96 mass %, preferably 10-90 mass %, inter alia, 20-80 mass %,        Polymerizable Unsaturated Monomeric Mixture (a-3)

Polymerizable unsaturated monomeric mixture (a-3) is a mixture of thefollowing polymerizable unsaturated monomer (m-6) and polymerizableunsaturated monomer (m-7) other than the polymerizable unsaturatedpolymer (m-6).

Polymerizable Unsaturated Monomer (m-6)

Polymerizable unsaturated monomer (m-6) is a compound having at leastone each of divalent group represented by the following general formula(I):

-   -   (in which R₁ stands for C₁₋₁₀, preferably C₂₋₆, alkylene group,        m is an integer of 1-30, preferably 1-20, inter alia, 1-10 and        the m recurring units,

-   -    may be the same or different),        phosphoric acid group represented by the following general        formula (II):

-   -   (in which R₂ stands for hydrogen atom or a C₁₋₂₀, in particular,        C₁₋₈ hydrocarbon group; preferably hydrogen atom)        and polymerizable unsaturated bond, per molecule.

The polymerizable unsaturated monomer (m-6) can be readily synthesizedby, for example, modifying hydroxyl-containing (meth)acrylates withcyclic ester, acting thereon a phosphorylation agent and thereafterhydrolyzing the product, according to the customarily practiced method.

As the hydroxyl-containing (meth)acrylates, for example, 2-hydroxyethyl(meth)acrylate and 2- or 3-hydroxypropyl (meth)acrylate can be named.

As the cyclic ester, for example, C₃₋₁₁ lactones such asβ-propiolactone, dimethylpropiolactone, γ-butyrolactone,γ-valerolactone, δ-valerolactone, γ-caprolactone, δ-caprolactone,ε-caprolactone, γ-caprylolactone and δ-laurolactone can be named, whichmay be used either alone or in combination of two or more. Of these,ε-caprolactone is preferred.

As the phosphorylation agent, those known per se, for example,phosphorus pentoxide, phosphorus oxychloride, polyphosphoric acid andthe like can be used.

Modification of hydroxyl-containing (meth)acrylates with cyclic estercan be effected by, for example, ring-opening addition of the cyclicester to hydroxyl groups in the hydroxyl-containing (meth)acrylates, bya method known per se. After reacting a phosphorylation agent with, forexample, terminal hydroxyl group in the resulting modification product,the phosphorylated product is hydrolyzed to provide the polymerizableunsaturated monomer (m-6).

Polymerizable unsaturated monomer (m-6) can further contain a unitrepresented by the following general formula (III):

R₃—O

_(i)  (III)

-   -   (in which R₃ stands for C₁₋₁₀, preferably C₂₋₄, more preferably        C₂ or C₃, inter alia, C₃, straight or branched chain alkylene        group; and i is an integer of 1-30, preferably 1-20, inter alia,        1-10, and the i oxyalkylene units,        R₃—O    -   may be the same or different).

The polymerizable unsaturated monomer (m-6) containing the above unit ofthe general formula (III) can be obtained by, for example, after thering-opening addition of cyclic ester to the hydroxyl groups inhydroxyl-containing (meth)acrylates by the means known per se, adding,for example, alkylene oxide to the terminal hydroxyl group in theresulting modification product, and further causing a knownphosphorylating agent such as phosphorus pentoxide or phosphorusoxychloride to act on, for example, the terminal hydroxyl group in theaddition product, followed by hydrolysis.

As the polymerizable unsaturated monomer (m-6), specifically thoserepresented by the following general formulae (IV), (V), (VII) and(VIII) can be named for example.

-   -   [in the formulae, X stands for oxygen atom or a group        represented by the following general formula (VI):

-   -   (here Y stands for hydrogen atom or C₁₋₈ alkyl, preferably        hydrogen atom); j is an integer of 0-30, preferably 0-20, inter        alia, 0-10; R₄ stands for hydrogen atom or methyl group; and R₅        stands for C₁₋₆, preferably C₂₋₄, inter alia, C₂ or C₃, alkylene        group; the m recurring units,

-   -   may be the same or different, the j oxyalkylene units,        R₃—O    -    may be the same or different, and R₁, R₃ and m have the same        definitions as previously given]

-   -   [in the formulae, X, R₁, R₄, R₅ and m have the same definitions        as previously given, R₆ stands for C₁₋₁₀, preferably C₂₋₆,        alkylene group, n is an integer of 1-30, preferably 1-20, inter        alia, 1-10, the m recurring units,

-   -   may be the same or different, the n recurring units,

-   -   may be the same or different, and the sequence order of the m        recurring units,

-   -   and the n recurring units,

-   -   may be in blocks or at random].

These polymerizable unsaturated monomers (m-6) can be used either aloneor in combination of two or more.

Polymerizable Unsaturated Monomer (m-7) other than the PolymerizableUnsaturated Monomer (m-6)

Polymerizable unsaturated monomers (m-7) are the polymerizableunsaturated monomers other than the above polymerizable unsaturatedmonomers (m-6), examples of which are: alkyl or cycloalkyl(meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate,n-propyl (meth)acrylate, i-propyl (meth)acrylate, n-butyl(meth)acrylate, i-butyl (meth)acrylate, tert-butyl (meth)acrylate,n-hexyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl(meth)acrylate, nonyl (meth)acrylate, tridecyl (meth)acrylate, lauryl(meth)acrylate, stearyl (meth)acrylate, “isostearyl acrylate”(tradename, Osaka Organic Chemical Industry Ltd.), cyclohexyl(meth)acrylate, methylcyclohexyl (meth)acrylate, t-butylcyclohexyl(meth)acrylate, cyclododecyl (meth)acrylate and tricyclodecanyl(meth)acrylate; polymerizable unsaturated monomers having isobornylgroup, such as isobornyl (meth)acrylate; polymerizable unsaturatedmonomers having adamantyl group, such as adamantyl (meth)acrylate;polymerizable unsaturated monomers having tricyclodecanyl group, such astricyclodecanyl (meth)acrylate; vinyl aromatic compounds such asstyrene, α-methylstyrene and vinyltoluene; polymerizable unsaturatedmonomers having alkoxysilyl group, such as vinyltrimethoxysilane,vinyltriethoxysilane, vinyltris(2-methoxyethoxy)silane,γ-(meth)acryloyloxypropyltri-methoxysilane andγ-(meth)acryloyloxypropyltriethoxysilane; perfluoroalkyl (meth)acrylatessuch as perfluorobutylethyl (meth)acrylate and perfluorooctylethyl(meth)acrylate; polymerizable unsaturated monomers having fluorinatedalkyl group such as fluoroolefin; polymerizable unsaturated monomershaving photo-polymerizable functional group like maleimido group; vinylcompounds such as N-vinylpyrrolidone, ethylene, butadiene, chloroprene,vinyl propionate and vinyl acetate; monoesterified products of(meth)acrylic acid with C₂₋₈ dihydric alcohols such as 2-hydroxyethyl(meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl(meth)acrylate and 4-hydroxybutyl (meth)acrylate; hydroxyl-containingpolymerizable unsaturated monomers such as ε-caprolactone-modifiedproducts of above monoesterified products of (meth)acrylic acid withC₂₋₈ dihydric alcohols, N-hydroxymethyl (meth)acrylamide, allyl alcoholand (meth)acrylate having hydroxyl-terminated polyoxyethylene chain;carboxyl-containing polymerizable unsaturated monomers such as(meth)acrylic acid, maleic acid, crotonic acid and β-carboxyethylacrylate; nitrogen-containing polymerizable unsaturated monomers such as(meth)acrylonitrile, (meth)acrylamide, N,N-dimethylaminoethyl(meth)acrylate, N,N-dimethylaminopropyl (meth)acrylamide and additionproducts of glycidyl (meth)acrylate with amines; polymerizableunsaturated monomers having at least two polymerizable unsaturatedgroups per molecule, such as allyl (meth)acrylate and 1,6-hexanedioldi(meth)acrylate; epoxy-containing polymerizable unsaturated monomerssuch as glycidyl (meth)acrylate, β-methylglycidyl (meth)acrylate,3,4-epoxycyclohexylmethyl (meth)acrylate, 3,4-epoxycyclohexylethyl(meth)acrylate, 3,4-epoxycyclohexylpropyl (meth)acrylate andallylglycidyl ether; (meth)acrylates having alkoxy-terminatedpolyoxyethylene chain; sulfonic acid group-containing polymerizableunsaturated monomers such as 2-acrylamido-2-methylpropanesulfonic acid,2-sulfoethyl (meth)acrylate, allylsulfonic acid, 4-styrenesulfonic acid,and sodium salts or ammonium salts of the foregoing; phosphoric acidgroup-containing polymerizable unsaturated monomers such as acidphosphoxyethyl (meth)acrylate, acid phosphoxypolyoxyethylene glycolmono(meth)acrylate and acid phosphoxypolyoxypropylene glycolmono(meth)acrylate; polymerizable unsaturated monomers having UVabsorbing functional group, such as2-hydroxy-4-(3-methacryloyloxy-2-hydroxypropoxy)benzophenone,2-hydroxy-4-(3-acryloyloxy-2-hydroxypropoxy)benzophenone,2,2′-dihydroxy-4-(3-methacryloyloxy-2-hydroxypropoxy)benzophenone,2,2′-dihydroxy-4-(3-acryloyloxy-2-hydroxypropoxy)benzophenone and2-(2′-hydroxy-5′-methacryloyloxyethylphenyl)-2H-benzotriazole; UV-stablepolymerizable unsaturated monomers such as4-(meth)acryloyloxy-1,2,2,6,6-pentamethylpiperidine,4-(meth)acryloyloxy-2,2,6,6-tetramethylpiperidine,4-cyano-4-(meth)acryloylamino-2,2,6,6-tetramethylpiperidine,1-(meth)acryloyl-4-(meth)acryloylamino-2,2,6,6-tetramethylpiperidine,1-(meth)acryloyl-4-cyano-4-meth)acryloylamino-2,2,6,6-tetramethylpiperidine,4-crotonoyloxy-2,2,6,6-tetramethylpiperidine,4-crotonoylamino-2,2,6,6-tetramethylpiperidine and1-crotonoyl-4-crotonoyloxy-2,2,6,6-tetramethylpiperidine; andcarbonyl-containing polymerizable unsaturated monomer compounds such asacrolein, diacetoneacrylamide, diacetonmethacrylamide, acetoacetoxyethylmethacrylate, formylstyrol and C₄₋₇ vinylalkylketones (e.g., vinylmethyl ketone, vinyl ethyl ketone, vinyl butyl ketone). These can beused either alone or in combination of two or more.

It is particularly preferred for the polymerizable unsaturated monomer(m-7), from the viewpoint of water resistance of the resulting coatingfilm, to contain at least one of the polymerizable unsaturated monomerselected from the group consisting of above vinyl aromatic compounds,polymerizable unsaturated monomers having C₆₋₁₈ alkyl groups andpolymerizable unsaturated monomers having C₆₋₁₈ cycloalkyl groups, amongwhich styrene being particularly preferred.

As examples of the polymerizable unsaturated monomers having C₆₋₁₈ alkylgroups, n-hexyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl(meth)acrylate, nonyl (meth)acrylate, tridecyl (meth)acrylate, lauryl(meth)acrylate, stearyl (meth)acrylate and “isostearyl acrylate”(tradename, Osaka Organic Chemical Industry Ltd.) can be named, whichmay be used either alone or in combination of two or more. Of these, useof polymerizable unsaturated monomers having C₈₋₁₃ alkyl groups, inparticular, 2-ethylhexyl (meth)acrylate and/or lauryl (meth)acrylate, ispreferred.

As examples of the polymerizable unsaturated monomers having C₆₋₁₈cycloalkyl groups, cyclohexyl (meth)acrylate, methylcyclohexyl(meth)acrylate, t-butylcyclohexyl (meth)acrylate, cyclododecyl(meth)acrylate, isobornyl (meth)acrylate, adamantyl (meth)acrylate andtricyclodecanyl (meth)acrylate can be named, which may be used eitheralone or in combination of two or more. Of these, use of polymerizableunsaturated monomers having C₈₋₁₃ cycloalkyl groups, in particular,cyclohexyl (meth)acrylate, is preferred.

Where the polymerizable unsaturated monomer (m-7) contains at least oneof the polymerizable unsaturated monomer selected from the groupconsisting of above vinyl aromatic compounds, polymerizable unsaturatedmonomers having C₆₋₁₈ alkyl groups and polymerizable unsaturatedmonomers having C₆₋₁₈ cycloalkyl groups, the combined use amount of thevinyl aromatic compound, polymerizable unsaturated monomer having C₆₋₁₈alkyl group and polymerizable unsaturated monomer having C₆₋₁₈cycloalkyl group is preferably within a range of generally 1-96 mass %,in particular, 10-70 mass %, inter alia, 20-60 mass %, based on thetotal amount of the polymerizable unsaturated monomers (m-1), (m-6) and(m-7).

Also where the polymerizable unsaturated monomer (m-7) contains styrene,the use amount of styrene is preferably within a range of generally 5-70mass %, in particular, 10-60 mass %, inter alia, 15-50 mass %, based onthe total amount of the polymerizable unsaturated monomers (m-6) and(m-7).

While the mixing ratio of those polymerizable unsaturated monomers (m-6)and (m-7) in the polymerizable unsaturated monomeric mixture (a-3) isnot strictly limited, generally it can be within the following ranges,based on the total amount of the polymerizable unsaturated monomers(m-6) and (m-7):

-   polymerizable unsaturated monomer (m-6):    -   1-90 mass %, preferably 5-70 mass %, inter alia, 20-60 mass %,-   polymerizable unsaturated monomer (m-7):    -   10-99 mass %, preferably 30-95 mass %, inter alia, 40-80 mass %,        Polymerizable Unsaturated Monomeric Mixture (a-4)

Polymerizable unsaturated monomeric mixture (a-4) is a mixture of thefollowing polymerizable unsaturated monomer (m-8) and polymerizableunsaturated monomer (m-9) other than the polymerizable unsaturatedmonomer (m-8).

Polymerizable Unsaturated Monomer (m-8)

Polymerizable unsaturated monomer (m-8) is a polymerizable unsaturatedmonomer containing a divalent group of the following general formula(I):

-   -   (in which R₁ and m have the previously given definitions, and        the m recurring units,

-   -    may be the same or different)        and sulfonic acid group.

Such a polymerizable unsaturated monomer (m-8) can be readilysynthesized by, for example, modifying hydroxyl-containing(meth)acrylates with cyclic ester, and sulfonating the hydroxyl group inthe resulting modification product with a sulfonation agent according tothe accepted practice.

As the hydroxyl-containing (meth)acrylates, for example, 2-hydroxyethyl(meth)acrylate and 2- or 3-hydroxypropyl (meth)acrylate can be named.

As the cyclic ester, for example, C₃₋₁₁ lactones such asβ-propiolactone, dimethylpropiolactone, γ-butyrolactone,γ-valerolactone, δ-valerolactone, γ-caprolactone, δ-caprolactone,ε-caprolactone, γ-caprylolactone and δ-laurolactone can be named, whichmay be used either alone or in combination of two or more. Of these,ε-caprolactone is preferred.

Also as the sulfonation agent, those known per se, such as sulfuricanhydride, fuming sulfuric acid, chlorosulfonic acid, sulfuric acid,sodium hydrogensulfite and the like, can be used.

Modification of hydroxyl-containing (meth)acrylates with cyclic estercan be effected by, for example, ring-opening addition of the cyclicester to hydroxyl groups in the hydroxyl-containing (meth)acrylates, bya method known per se. Then reacting a sulfonation agent with, forexample, terminal hydroxyl group in the resulting modified product tosulfonate the same, a polymerizable unsaturated monomer (m-8) can beobtained.

The polymerizable unsaturated monomer (m-8) can further contain a unitrepresented by the following general formula (III):

R₃—O

_(i)  (III)

-   -   (in which R₃ and i have the same definitions to those given        previously, and the i oxyalkylene units,        R₃—O    -   may be the same or different).

The polymerizable unsaturated monomer (m-8) containing the above unit ofthe general formula (III) can be obtained by, for example, after thering-opening addition of cyclic ester to the hydroxyl groups inhydroxyl-containing (meth)acrylates by the means known per se, adding,for example, alkylene oxide to the terminal hydroxyl group in theresulting modification product, and further causing a known sulfonationagent such as conc. sulfuric acid, fuming sulfuric acid, sulfurtrioxide, chlorosulfonic acid, sodium sulfite or the like to act on, forexample, the terminal hydroxyl group in the addition product.

As the polymerizable unsaturated monomer (m-8), specifically thoserepresented by the following general formulae (IX), (X), (XI) and (XII)can be named:

-   -   (in the formulae, X, R₁, R₃, R₄, R₅, m and j have the previously        given definitions, and the m recurring units,

-   -   may be the same or different, and the j oxyalkylene units        R₃—O    -    may be the same or different),

-   -   (in which X, R₁, R₄, R₅, R₆, m and n have the previously given        definitions, the m recurring units,

-   -   may be the same or different, the n-recurring units,

-   -   may be the same or different, and the sequence order of the m        recurring units,

-   -   and the n recurring units,

-   -    may be in blocks or at random).

These polymerizable unsaturated monomers (m-8) can be used either aloneor in combination of two or more.

Polymerizable Unsaturated Monomer (m-9) other than the PolymerizableUnsaturated Monomer (m-8)

Polymerizable unsaturated monomers (m-9) are the polymerizableunsaturated monomers other than the above polymerizable unsaturatedmonomers (m-8), examples of which are: alkyl or cycloalkyl(meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate,n-propyl (meth)acrylate, i-propyl (meth)acrylate, n-butyl(meth)acrylate, i-butyl (meth)acrylate, tert-butyl (meth)acrylate,n-hexyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl(meth)acrylate, nonyl (meth)acrylate, tridecyl (meth)acrylate, lauryl(meth)acrylate, stearyl (meth)acrylate, “isostearyl acrylate”(tradename, Osaka Organic Chemical Industry Ltd.), cyclohexyl(meth)acrylate, methylcyclohexyl (meth)acrylate, t-butylcyclohexyl(meth)acrylate, cyclododecyl (meth)acrylate and tricyclodecanyl(meth)acrylate; polymerizable unsaturated monomers having isobornylgroup, such as isobornyl (meth)acrylate; polymerizable unsaturatedmonomers having adamantyl group, such as adamantyl (meth)acrylate;polymerizable unsaturated monomers having tricyclodecanyl group, such astricyclodecanyl (meth)acrylate; vinyl aromatic compounds such asstyrene, α-methylstyrene and vinyltoluene; polymerizable unsaturatedmonomers having alkoxysilyl group, such as vinyltrimethoxysilane,vinyltriethoxysilane, vinyltris(2-methoxyethoxy)silane,γ-(meth)acryloyloxypropyltrimethoxysilane andγ-(meth)acryloyloxypropyltriethoxysilane; perfluoroalkyl (meth)acrylatessuch as perfluorobutylethyl (meth)acrylate and perfluorooctylethyl(meth)acrylate; polymerizable unsaturated monomers having fluorinatedalkyl group such as fluoroolefin; polymerizable unsaturated monomershaving photo-polymerizable functional group like maleimido group; vinylcompounds such as N-vinylpyrrolidone, ethylene, butadiene, chloroprene,vinyl propionate and vinyl acetate; monoesterified products of(meth)acrylic acid with C₂₋₈ dihydric alcohols such as 2-hydroxyethyl(meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl(meth)acrylate and 4-hydroxybutyl (meth)acrylate; hydroxyl-containingpolymerizable unsaturated monomers such as ε-caprolactone-modifiedproducts of above monoesterified products of (meth)acrylic acid withC₂₋₈ dihydric alcohols, N-hydroxymethyl (meth)acrylamide, allyl alcoholand (meth)acrylate having hydroxyl-terminated polyoxyethylene chain;carboxyl-containing polymerizable unsaturated monomers such as(meth)acrylic acid, maleic acid, crotonic acid and β-carboxyethylacrylate; nitrogen-containing polymerizable unsaturated monomers such as(meth)acrylonitrile, (meth)acrylamide, N,N-dimethylaminoethyl(meth)acrylate, N,N-dimethylaminopropyl (meth)acrylamide and additionproducts of glycidyl (meth)acrylate with amines; polymerizableunsaturated monomers having at least two polymerizable unsaturatedgroups per molecule, such as allyl (meth)acrylate and 1,6-hexanedioldi(meth)acrylate; epoxy-containing polymerizable unsaturated monomerssuch as glycidyl (meth)acrylate, β-methylglycidyl (meth)acrylate,3,4-epoxycyclohexylmethyl (meth)acrylate, 3,4-epoxycyclohexylethyl(meth)acrylate, 3,4-epoxycyclohexylpropyl (meth)acrylate andallylglycidyl ether; (meth)acrylates having alkoxy-terminatedpolyoxyethylene chain; sulfonic acid group-containing polymerizableunsaturated monomers such as 2-acrylamido-2-methylpropanesulfonic acid,2-sulfoethyl (meth)acrylate, allylsulfonic acid, 4-styrenesulfonic acid,and sodium salts or ammonium salts of the foregoing; phosphoric acidgroup-containing polymerizable unsaturated monomers such as acidphosphoxyethyl (meth)acrylate, acid phosphoxypolyoxyethylene glycolmono(meth)acrylate and acid phosphoxypolyoxypropylene glycolmono(meth)acrylate; polymerizable unsaturated monomers having UVabsorbing functional group, such as2-hydroxy-4-(3-methacryloyloxy-2-hydroxypropoxy)benzophenone,2-hydroxy-4-(3-acryloyloxy-2-hydroxypropoxy)benzophenone,2,2′-dihydroxy-4-(3-methacryloyloxy-2-hydroxypropoxy)benzophenone,2,2′-dihydroxy-4-(3-acryloyloxy-2-hydroxypropoxy)benzophenone and2-(2′-hydroxy-5′-methacryloyloxyethylphenyl)-2H-benzotriazole; UV-stablepolymerizable unsaturated monomers such as4-(meth)acryloyloxy-1,2,2,6,6-pentamethylpiperidine,4-(meth)acryloyloxy-2,2,6,6-tetramethylpiperidine,4-cyano-4-(meth)acryloylamino-2,2,6,6-tetramethylpiperidine,1-(meth)acryloyl-4-(meth)acryloylamino-2,2,6,6-tetramethylpiperidine,1-(meth)acryloyl-4-cyano-4-meth)acryloylamino-2,2,6,6-tetramethylpiperidine,4-crotonoyloxy-2,2,6,6-tetramethylpiperidine,4-crotonoylamino-2,2,6,6-tetramethylpiperidine and1-crotonoyl-4-crotonoyloxy-2,2,6,6-tetramethylpiperidine; andcarbonyl-containing polymerizable unsaturated monomer compounds such asacrolein, diacetoneacrylamide, diacetonmethacrylamide, acetoacetoxyethylmethacrylate, formylstyrol and C₄₋₇ vinylalkylketones (e.g., vinylmethyl ketone, vinyl ethyl ketone, vinyl butyl ketone). These can beused either alone or in combination of two or more.

It is particularly preferred for the polymerizable unsaturated monomer(m-9), from the viewpoint of water resistance of the resulting coatingfilm, to contain at least one of the polymerizable unsaturated monomerselected from the group consisting of above vinyl aromatic compounds,polymerizable unsaturated monomers having C₆₋₁₈ alkyl groups andpolymerizable unsaturated monomers having C₆₋₁₈ cycloalkyl groups, amongwhich styrene being particularly preferred.

As examples of the polymerizable unsaturated monomers having C₆₋₁₈ alkylgroups, n-hexyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl(meth)acrylate, nonyl (meth)acrylate, tridecyl (meth)acrylate, lauryl(meth)acrylate, stearyl (meth)acrylate and “isostearyl acrylate”(tradename, Osaka Organic Chemical Industry Ltd.) can be named, whichmay be used either alone or in combination of two or more. Of these, useof polymerizable unsaturated monomers having C₈₋₁₃ alkyl groups, inparticular, 2-ethylhexyl (meth)acrylate and/or lauryl (meth)acrylate, ispreferred.

As examples of the polymerizable unsaturated monomers having C₆₋₁₈cycloalkyl groups, cyclohexyl (meth)acrylate, methylcyclohexyl(meth)acrylate, t-butylcyclohexyl (meth)acrylate, cyclododecyl(meth)acrylate, isobornyl (meth)acrylate, adamantyl (meth)acrylate andtricyclodecanyl (meth)acrylate can be named, which may be used eitheralone or in combination of two or more. Of these, use of polymerizableunsaturated monomers having C₈₋₁₃ cycloalkyl groups, in particular,cyclohexyl (meth)acrylate, is preferred.

Where the polymerizable unsaturated monomer (m-9) contains at least oneof the polymerizable unsaturated monomer selected from the groupconsisting of above vinyl aromatic compounds, polymerizable unsaturatedmonomers having C₆₋₁₈ alkyl groups and polymerizable unsaturatedmonomers having C₆₋₁₈ cycloalkyl groups, the combined use amount of thevinyl aromatic compound, polymerizable unsaturated monomer having C₆₋₁₈alkyl group and polymerizable unsaturated monomer having C₆₋₁₈cycloalkyl group is preferably within a range of generally 1-96 mass %,in particular, 10-70 mass %, inter alia, 20-60 mass %, based on thetotal amount of the polymerizable unsaturated monomers (m-8) and (m-9).

Also where the polymerizable unsaturated monomer (m-9) contains styrene,the use amount of styrene is preferably within a range of generally 5-70mass %, in particular, 10-60 mass %, inter alia, 15-50 mass %, based onthe total amount of the polymerizable unsaturated monomers (m-8) and(m-9).

While the mixing ratio of those polymerizable unsaturated monomers (m-8)and (m-9) in the polymerizable unsaturated monomeric mixture (a-4) isnot strictly limited, generally it can be within the following ranges,based on the total amount of the polymerizable unsaturated monomers(m-8) and (m-9):

-   polymerizable unsaturated monomer (m-8):    -   1-90 mass %, preferably 5-70 mass %, inter alia, 20-60 mass %,-   polymerizable unsaturated monomer (m-9):    -   10-99 mass %, preferably 30-95 mass %, inter alia, 40-80 mass %,        Pigment-dispersing Resin (A)

According to the present invention, copolymerizing a polymerizableunsaturated monomeric mixture (a) selected from the above-describedpolymerizable unsaturated monomeric mixtures (a-1) to (a-4), preferablythe polymerizable unsaturated monomeric mixture (a-1) or (a-3), in areaction solvent (b) which contains at least 30 mass %, based on thetotal amount of the reaction solvent, of an organic solvent (b-1) whichdoes not contain hydroxyl group and has a solubility in water at 20° C.of at least 100 mass %, a pigment-dispersing resin (A) having divalentgroups of the general formula, (I):

-   -   (in which R₁ and m have the previously given definitions, and        the m recurring units,

-   -    may be the same or different),        phosphoric acid groups and/or sulfonic acid groups can be        produced.        Organic Solvent (b-1)

The organic solvent (b-1) is an organic solvent which does not containhydroxyl group and has a solubility in water at 20° C. of at least 100mass %. In the present invention, “an organic solvent having asolubility in water at 20° C. of at least 100 mass %” refers to anorganic solvent which, when 5 g of the organic solvent and 5 g of waterare put in an agitating container and shaken at 20° C. for 5 minutes, noturbidity or phase separation is visually observable in the resultingliquid mixture which is in homogeneous state.

As the organic solvent (b-1), for example, ether solvents such as1,4-dioxane, tetrahydrofuran, ethylene glycol dimethyl ether, diethyleneglycol dimethyl ether, propylene glycol dimethyl ether and dipropyleneglycol dimethyl ether; amide solvents such as N,N-dimethylacetamide,N,N-dimethylformamide, N-methyl-2-pyrrolidone andN,N-dimethyl-β-methoxypropionamide; urea solvents such as1,3-dimethyl-2-imidazolidinone; sulfoxide solvents such asdimethylsulfoxide; and sulfone solvents such as tetramethylenesulfonecan be named, which are useful either alone or in combination of two ormore. Of these, above ether solvents, amide solvents and urea solventsare preferred as the organic solvent (b-1), amide solvents beingparticularly preferred.

Reaction Solvent (b)

The reaction solvent (b) contains at least 30 mass %, preferably 50-100mass %, in particular, 80-100 mass %, inter alia, 95-100 mass % of aboveorganic solvent (b-1), based on the total mass of the reaction solvent(b).

Examples of organic solvents other than the organic solvent (b-1), whichthe reaction solvent (b) can contain, include: hydrocarbon solvents suchas heptane, toluene, xylene, octane and mineral spirit; ester solventssuch as ethyl acetate, n-butyl acetate, isobutyl acetate, ethyleneglycol monomethyl ether acetate and diethylene glycol monobutyl etheracetate; ketone solvents such as methyl ethyl ketone, methyl isobutylketone, diisobutyl ketone and cyclohexanone; ether solvents such asn-butyl ether, ethylene glycol monomethyl ether and ethylene glycolmonoethyl ether; and aromatic petroleum solvents such as SWAZOL 310,SWAZOL 1000, SWAZOL 1500 and the like of COSMO OIL Co., Ltd. Theseorganic solvents can be used either alone or in combination of two ormore.

Copolymerization

Copolymerization of the polymerizable unsaturated monomeric mixture (a)can be conducted by any methods known per se, among which solutionpolymerization in an organic solvent being preferred. As thecopolymerization process by the solution polymerization, for example, aprocess comprising dissolving or dispersing a mixture of a polymerizableunsaturated monomeric mixture (a) with a radical polymerizationinitiator in a reaction solvent (b), and polymerizing the same byheating at temperatures of normally from about 80° C. to about 200° C.for around 1-10 hours under stirring, can be used. In the polymerizationreaction, the reaction solvent (b) may be used at a ratio normallyranging 10-300 mass parts, preferably 30-200 mass parts, inter alia,50-150 mass parts, per 100 mass parts of the polymerizable unsaturatedmonomeric mixture (a).

As the radical polymerization initiator, for example, organoperoxidepolymerization initiators including ketone peroxides such ascyclohexanone peroxide, 3,3,5-trimethylcyclohexanone peroxide andmethylcyclohexanone peroxide; peroxyketals such as1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane,1,1-bis(tert-butylperoxy)cyclohexane andn-butyl-4,4-bis(tert-butylperoxy)valerate; hydroperoxides such as cumenehydroperoxide and 2,5-dimethylhexane-2,5-dihydroperoxide; dialkylperoxides such as 1,3-bis(tert-butylperoxy-m-isopropyl)benzene,2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, diisopropylbenzene peroxideand tert-butylcumyl peroxide; diacyl peroxides such as decanoylperoxide, lauroyl peroxide, benzoyl peroxide and 2,4-dichlorobenzoylperoxide; peroxy carbonates such asbis(tert-butylcyclohexyl)-peroxydicarbonate; and peroxyesters such astert-butylperoxybenzoate and 2,5-dimethyl-2,5-di(benzolyperoxy)hexane:and azo polymerization initiators including 2,2′-azobisisobutyronitrile,1,1-azobis(cyclohexane-1-carbonitrile), azocumene2,2′-azobismethylvaleronitrile and 4,4′-azobis(4-cyanovaleric acid) canbe named. While use amount of these radical polymerization initiators isnot particularly limited, desirably it is within a range of normally0.1-15 mass parts, in particular, 0.3-10 mass parts, per 100 mass partsof the polymerizable unsaturated monomeric mixture (a).

The method of adding the monomeric components or polymerizationinitiator in the above polymerization reaction is subject to noparticular limitation, but from the viewpoints of temperature controlduring the polymerization reaction and suppression of occurrence of poorcrosslinked product such as gelated product, it is recommendable to addthe polymerization initiator dropwise, as divided into plural portionsover from the initial stage of polymerization to the late stage, ratherthan feeding it all at once in the initial stage of the polymerization.

Thus obtained pigment-dispersing resin (A) suitably has an acid valuewithin a range of generally 30-200 mgKOH/g, in particular 45-180mgKOH/g, inter alia, 60-150 mgKOH/g, from the viewpoint of waterresistance of the resulting coating film.

In the subject specification the “acid value” is determined as follows.A test sample is dissolved or dispersed in propylene glycol monomethylether, and titrated at 25° C. with an ethanol solution of potassiumhydroxide, using phenolphthalein as the indicator, the point at whichthe tested liquid turns pale pink is recorded as the end point, and fromwhich the value is calculated according to the following equation:acid value (mgKOH/g)=56.1×V×C/m

-   -   V=volume of the titrant added (ml),    -   C=concentration of the titrant (mol/l),    -   m=solid weight of the test sample (g).

Also from the viewpoint of water resistance of the resulting coatingfilm, the pigment-dispersing resin (A) preferably has a hydroxyl valuewithin a range of generally 10-200 mgKOH/g, in particular, 20-180mgKOH/g, inter alia, 30-150 mgKOH/g.

Furthermore, from the viewpoint of the appearance and water resistanceof the resulting coating film, the pigment-dispersing resin (A)preferably has a number-average molecular weight within a range ofgenerally 2,000-200,000, in particular, 4,000-100,000, inter alia,10,000-50,000.

In the present specification, “number-average molecular weight” and“weight-average molecular weight” are determined by converting thenumber-average molecular weight or weight-average molecular weight asmeasured with gel permeation chromatograph (HLC8120GPC, tradename, TosohCorporation), based on the molecular weight of standard polystyrene. Themeasurement is conducted using four columns of TSKgel G-4000HXL, TSKgelG-3000HXL, TSKgel G-2500HXL and TSKgel G-2000HXL (tradename, TosohCorporation) under the conditions of mobile phase: tetrahydrofuran,measuring temp.: 40° C., flow rate: 1 cc/min. and detector: RI.

The pigment-dispersing resin (A) preferably contains the divalentgroup(s) represented by the following general formula (I):

-   -   (in which R₁ and m have the previously given definitions, and        the m recurring units,

-   -    may be the same or different)        at a mass ratio within a range of generally 1-70 mass %, in        particular, 5-60 mass %, inter alia, 10-50 mass %, based on the        mass of the pigment-dispersing resin (A).        Pigment Dispersion

The pigment-dispersing resin (A) as prepared in the above manner can beformed into a pigment dispersion, upon being mixed with pigment (B), andwhere necessary, solvent, pigment-dispersing agent, and other additives.

Pigment (B)

Examples of pigment (B) include effect pigments (B1) such as aluminium,copper, brass, nickel, aluminium oxide, mica, aluminium oxide coatedwith titanium oxide or iron oxide, mica coated with titanium oxide oriron oxide, and bright graphite; coloring pigments (B2) such as titaniumdioxide, zinc flower, Carbon Black, red iron oxide, Molybdate Red,Prussian Blue, Cobalt Blue, azo pigment, phthalocyanine pigment,quinacridone pigment, isoindoline pigment, vat pigment, perylenepigment, dioxazine pigment, isoindolinone pigment anddiketopyrrolopyrrole pigment; extenders (B3) such as clay, kaoline,barium sulfate, barium carbonate, calcium carbonate, talc, silica,alumina white and the like. They can be used either alone or incombination of two or more. Those pigments may also be those given a perse known surface treatment, such as acid treatment, base treatment,coupling agent treatment, plasma treatment, oxidation treatment,reduction treatment or the like.

As the pigment (B), use of, the effect pigment (B1) and/or coloringpigment (B2) is preferred, in particular, use of the effect pigment ispreferred.

As the effect pigment (B1), use of, for example, aluminium, aluminiumoxide, mica, titanium dioxide- or iron oxide-coated aluminium oxide ortitanium dioxide- or iron oxide-coated mica is preferred, in particular,use of aluminium is preferred.

The effect pigment (B1) is preferably in the form of flakes. For theflaky effect pigment (B1), it is adequate to have a longitudinaldimension of around 1-100 μm, preferably around 5-40 μm, and a thicknessof around 0.001-5 μm, preferably 0.01-2 μm.

Again, where the effect pigment (B1), in particular, aluminium pigment,is used as at least a part of the pigment (B), the pigment-dispersingresin (A) is preferably a copolymer of the polymerizable unsaturatedmonomeric mixture (a-1) and/or a copolymer of the polymerizableunsaturated monomeric mixture (a-3), a copolymer of the polymerizableunsaturated monomeric mixture (a-3) being particularly preferred, fromthe viewpoint of excellent appearance of the resulting coating film.

While the blend ratio of the pigment (B) is subject to no particularlimitation, it is preferably within a range of normally 10-3,000 massparts, in particular, 15-2,000 mass parts, inter alia, 20-1,500 massparts, per 100 mass parts of solid resin content of thepigment-dispersing resin (A).

As the solvent to be used where necessary, water and/or organic solventcan be named. Examples of the organic solvent include: hydrocarbonsolvents such as toluene, xylene and mineral spirit; ester solvents suchas ethyl acetate, n-butyl acetate, isobutyl acetate, ethylene glycolmonomethyl ether acetate and butyl carbitol acetate; ketone solventssuch as methyl ethyl ketone, methyl isobutyl ketone and diisobutylketone; alcohol solvents such as methanol, ethanol, isopropanol,1-butanol, 2-butanol, isobutanol, 1-hexanol, 1-octanol, 2-octanol,2-ethylhexanol, 1-decanol, benzyl alcohol, diethylene glycol, ethyleneglycol monomethyl ether, ethylene glycol monoethyl ether, ethyleneglycol mono-2-ethylhexyl ether, propylene glycol mono-n-butyl ether,dipropylene glycol mono-n-butyl ether, tripropylene glycol mono-n-butylether, propylene glycol mono-2-ethylhexyl ether and propylene glycolmonophenyl ether; ether solvents such as ethyl butyl ether, dibutylether, diisobutyl ether, 1,4-dioxane, ethylene glycol dimethyl ether,diethylene glycol dimethyl ether, propylene glycol dimethyl ether anddipropylene glycol dimethyl ether; amide solvents such asN,N-dimethylacetamide, N,N-dimethylformamide, N-methyl-2-pyrrolidone andN,N-dimethyl-β-methoxypropionamide; and aromatic petroleum solvents suchas SWAZOL 310, SWAZOL 1000 and SWAZOL 1500 made by COSMO Oil Co., Ltd.These organic solvents can be used either alone or as a mixture of twoor more.

Where the pigment dispersion contains such solvent(s) as describedabove, the blend ratio of the solvent is not critical, but preferably itis within a range of normally 50-5,000 mass parts, in particular,100-3,000 mass parts, inter alia, 100-2,000 mass parts, per 100 massparts of the solid resin content of the pigment-dispersing resin (A).

The pigment dispersion can be prepared by uniformly mixing anddispersing the above-described components with, for example, paintshaker, Skandex, dispersing device or the like.

Paint Compositions

The pigment dispersion as prepared in the above can be formulated into apaint composition, as mixed with binder resin for paint and, wherenecessary, various paint additives such as solvent, curing catalyst,fine polymer particles, ultraviolet absorber, light stabilizer,thickener, basic neutralizer, coated surface regulating agent,antioxidant, silane coupling agent and the like. The paint compositionpreferably is water-based.

“Water-based paint” is a term used in contradistinction to “organicsolvent-based paint”, and generally signifies paint which is formed bydispersing and/or dissolving binder resin for paint, pigment and thelike in water or a medium whose chief component is water (aqueousmedium). Where a paint composition is water-based, it convenientlycontains 10-90 mass parts, preferably 20-80 mass parts, inter alia,30-70 mass parts, of water, per 100 mass parts of the paint composition,for reducing environmental load.

The binder resin for paint encompasses combinations of base resin andcuring agent (D) which are customarily used in the field of paint. Asthe base resin, those which have been conventionally used forwater-based paint and which are known per se can be used, for example,water-soluble or water-dispersible resins based on alkyd resins, acrylicresins, polyester resins, polyurethane resins and the like. These resinspreferably contain in their molecules crosslinkable functional groupssuch as hydroxyl, carboxyl or epoxy groups. In particular, base resinspreferably are hydroxy-containing resins (C), inter alia,hydroxyl-containing acrylic resin (C1) and/or hydroxyl-containingpolyester resin (C2).

Hydroxyl-containing acrylic resin (C1) can be produced by(co)polymerizing a polymerizable unsaturated monomeric componentcomprising hydroxyl-containing polymerizable unsaturated monomer (c-1)hereinafter described, by a method known per se, for example, solutionpolymerization in organic solvent, emulsion polymerization in water, orthe like.

Hydroxyl-containing polymerizable unsaturated monomer (c-1) is acompound containing at least one each of hydroxyl group andpolymerizable unsaturated bond per molecule, examples of which includingmonoesterified products of (meth)acrylic acid with C₂₋₈ dihydricalcohols, such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl(meth)acrylate, 3-hydroxypropyl (meth)acrylate and 4-hydroxybutyl(meth)acrylate; ε-caprolactone-modified products of the monoesterifiedproducts of (meth)acrylic acid with C₂₋₈ dihydric alcohols;N-hydroxymethyl (meth)acrylamide; allyl alcohol, and (meth)acrylatehaving polyoxyethylene chain of which molecular terminal is hydroxylgroup. These monomers (c-1) can be used either alone or in combinationof two or more.

As other polymerizable unsaturated monomers which can be copolymerizedwith such hydroxyl-containing polymerizable unsaturated monomers (c-1),for example, alkyl or cycloalkyl (meth)acrylates such as methyl(meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, i-propyl(meth)acrylate, n-butyl (meth)acrylate, i-butyl (meth)acrylate,tert-butyl (meth)acrylate, n-hexyl (meth)acrylate, n-octyl(meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate,tridecyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate,“isostearyl acrylate” (tradename, Osaka Organic Chemical Industry Ltd.),cyclohexyl (meth)acrylate, methylcyclohexyl (meth)acrylate,t-butylcyclohexyl (meth)acrylate, and cyclododecyl (meth)acrylate;polymerizable unsaturated monomers having isobornyl group, such asisobornyl (meth)acrylate; polymerizable unsaturated monomers havingadamantyl group, such as adamantyl (meth)acrylate; vinyl aromaticcompounds such as styrene, α-methylstyrene and vinyltoluene;polymerizable unsaturated monomers having alkoxysilyl group, such asvinyltrimethoxysilane, vinyltriethoxysilane,vinyltris(2-methoxyethoxy)silane,γ-(meth)acryloyloxypropyltrimethoxysilane andγ-(meth)acryloyloxypropyltriethoxysilane; perfluoroalkyl (meth)acrylatessuch as perfluorobutylethyl (meth)acrylate and perfluorooctylethyl(meth)acrylate; polymerizable unsaturated monomers having fluorinatedalkyl group such as fluoroolefin; polymerizable unsaturated monomershaving photo-polymerizable functional group like maleimido group; vinylcompounds such as N-vinylpyrrolidone, ethylene, butadiene, chloroprene,vinyl propionate and vinyl acetate; carboxyl-containing polymerizableunsaturated monomers such as (meth)acrylic acid, maleic acid, crotonicacid and β-carboxyethyl acrylate; nitrogen-containing polymerizableunsaturated monomers such as (meth)acrylonitrile, (meth)acrylamide,N,N-dimethylaminoethyl (meth)acrylate, N,N-dimethylaminopropyl(meth)acrylamide and addition products of glycidyl (meth)acrylate withamines; polymerizable unsaturated monomers having at least twopolymerizable unsaturated groups per molecule, such as allyl(meth)acrylate and 1,6-hexanediol di(meth)acrylate; epoxy-containingpolymerizable unsaturated monomers such as glycidyl (meth)acrylate,β-methylglycidyl (meth)acrylate, 3,4-epoxycyclohexylmethyl(meth)acrylate, 3,4-epoxycyclohexylethyl (meth)acrylate,3,4-epoxycyclohexylpropyl (meth)acrylate and allylglycidyl ether;(meth)acrylates having alkoxy-terminated polyoxyethylene chain; sulfonicacid group-containing polymerizable unsaturated monomers such as2-acrylamido-2-methylpropanesulfonic acid, allylsulfonic acid,styrenesulfonic acid and sulfoethyl methacrylate; sodium salts orammonium salts of the sulfonic acid group-containing polymerizableunsaturated monomers; polymerizable unsaturated monomers havingphosphoric acid group such as 2-acryloyloxyethyl acid phosphate,2-methacryloyloxyethyl acid phosphate, 2-acryloyloxypropyl acidphosphate and 2-methacryloyloxypropyl acid phosphate; polymerizableunsaturated monomers having UV absorbing functional group, such as2-hydroxy-4-(3-methacryloyloxy-2-hydroxypropoxy)benzophenone,2-hydroxy-4-(3-acryloyloxy-2-hydroxypropoxy)benzophenone,2,2′-dihydroxy-4-(3-methacryloyloxy-2-hydroxypropoxy)benzophenone,2,2′-dihydroxy-4-(3-acryloyloxy-2-hydroxypropoxy)benzophenone and2-(2′-hydroxy-5′-methacryloyloxyethylphenyl)-2H-benzotriazole; UV-stablepolymerizable unsaturated monomers such as4-(meth)acryloyloxy-1,2,2,6,6-pentamethylpiperidine,4-(meth)acryloyloxy-2,2,6,6-tetramethylpiperidine,4-cyano-4-(meth)acryloylamino-2,2,6,6-tetramethylpiperidine1-(meth)acryloyl-4-(meth)acryloylamino-2,2,6,6-tetramethylpiperidine,1-(meth)acryloyl-4-cyano-4-(meth)acryloylamino-2,2,6,6-tetramethylpiperidine,4-crotonoyloxy-2,2,6,6-tetramethylpiperidine,4-crotonoylamino-2,2,6,6-tetramethylpiperidine and1-crotonoyl-4-crotonoyloxy-2,2,6,6-tetramethylpiperidine;carbonyl-containing polymerizable unsaturated monomers such as acrolein,diacetoneacrylamide, diacetonmethacrylamide, acetoacetoxyethylmethacrylate, formylstyrol and C₄₋₇ vinyl alkyl ketones (e.g., vinylmethyl ketone, vinyl ethyl ketone, vinyl butyl ketone); andpolymerizable unsaturated monomers having cationic functional group suchas tertiary amino group, quaternary ammonium salt group or the like.These polymerizable unsaturated monomers (a2-2) can be used either aloneor in combination of two or more.

The hydroxyl-containing acrylic resin (C1) preferably also containsamido group. Hydroxyl-containing acrylic resin having amido groups canbe produced, for example, by using as at least a part of the otherpolymerizable unsaturated monomer which is copolymerizable with thehydroxyl-containing polymerizable unsaturated monomer (c-1),amido-containing polymerizable unsaturated monomer such as(meth)acrylamide, N-methylol (meth)acrylamide andN,N-dimethylaminopropyl (meth)acrylamide.

From the viewpoint of storage stability and water resistance ofresulting coating film, the hydroxyl-containing acrylic resin (C1)preferably has a hydroxyl value within a range of normally 1-200mgKOH/g, in particular, 2-80 mgKOH/g, inter alia, 5-50 mgKOH/g.

Where the hydroxyl-containing acrylic resin (C1) contains an acid groupsuch as carboxyl group, it preferably has an acid value within a rangeof normally 5-150 mgKOH/g, in particular, 10-100 mgKOH/g, inter alia,15-70 mgKOH/g, from the viewpoint of water resistance of the resultingcoating film.

Furthermore, the hydroxyl-containing acrylic resin (C1) suitably has aweight-average molecular weight within a range of generally2,000-1,000,000, in particular, 3,000-200,000, inter alia,5,000-100,000.

The hydroxyl-containing acrylic resin (C1) is preferably a core-shelltype water-dispersible acrylic resin (C1′) composed of a core partformed of a copolymer (I) obtained from a monomeric mixture of 0.1-30mass % of a polymerizable unsaturated monomer (c-2) having at least twopolymerizable unsaturated groups per molecule and 70-99.9 mass % of apolymerizable unsaturated monomer (c-3) having one polymerizableunsaturated group per molecule; and a shell part formed of a copolymer(II) obtained from a monomeric mixture of 1-35 mass % of thehydroxyl-containing unsaturated monomer (c-1), 5-60 mass % ofhydrophobic polymerizable unsaturated monomer (c-4) and 5-94 mass % ofstill other polymerizable unsaturated monomer (c-5) from the viewpointof the appearance and water resistance of the resulting coating film;the ratio of the copolymer (I)/copolymer (II) being within a range of,in terms of solid mass ratio, 10/90-90/10, in particular, 50/50-85/15,inter alia, 65/35-80/20, for improving appearance of the coating film.

In the present specification, “polymerizable unsaturated group”signifies radical-polymerizable unsaturated group. As such polymerizableunsaturated group, for example, vinyl group and (meth)acryloyl group canbe named.

Examples of the monomer (c-2) include: allyl (meth)acrylate, ethyleneglycol di(meth)acrylate, triethylene glycol di(meth)acrylate,tetraethylene glycol di(meth)acrylate, 1,3-butylene glycoldi(meth)acrylate, trimethylolpropane tri(meth)acrylate, 1,4-butanedioldi(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,6-hexanedioldi(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritoltetra(meth)acrylate, glycerol di(meth)acrylate,1,1,1-trishydroxymethylethane di(meth)acrylate,1,1,1-trishydroxymethylethane tri(meth)acrylate,1,1,1-trishydroxymethylpropane tri(meth)acrylate, triallyl isocyanurate,diallyl terephthalate, divinylbenzene, methylenebis(meth)acrylamide andethylenebis(meth)acrylamide. These monomers can be used either alone orin combination of two or more.

The monomer (c-2) has the function to impart a crosslinked structure tothe core part copolymer (I), and the use ratio of the monomer (c-2) canbe suitably decided according to the extent of crosslinkage of the corepart copolymer (I). Whereas, it is generally preferred to use it withina range of normally 0.1-30 mass %, in particular, 0.5-10 mass %, interalia, 1-7 mass %, based on the total amount of the monomers (c-2) and(c-3).

As the monomer (c-2), use of polymerizable unsaturated monomer (c-2′)having at least two polymerizable unsaturated groups and at least oneamido group per molecule is preferred, for the excellent appearance ofthe resulting coating film. Examples of the monomer (c-2′) includemethylenebis(meth)acrylamide and ethylenebis(meth)acrylamide. Thesemonomers can be used either alone or in combination of two or more. Whenused, the preferred amount of the monomer (c-2′) is within a range ofnormally 0.1-25 mass %, in particular, 0.5-9 mass %, inter alia, 1-4mass %, based on the total amount of the monomers (c-2) and (c-3).

The monomer (c-3) which is used as the monomer for the core partcopolymer (I) is such that is copolymerizable with the polymerizableunsaturated monomer (c-2) having at least two polymerizable unsaturatedgroups per molecule. Specific examples of the monomer (c-3) includealkyl or cycloalkyl (meth)acrylates such as methyl (meth)acrylate, ethyl(meth)acrylate, n-propyl (meth)acrylate, i-propyl (meth)acrylate,n-butyl (meth)acrylate, i-butyl (meth)acrylate, tert-butyl(meth)acrylate, n-hexyl (meth)acrylate, n-octyl (meth)acrylate,2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, tridecyl(meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate,“isostearyl acrylate” (tradename, Osaka Organic Chemical Industry Ltd.),cyclohexyl (meth)acrylate, methylcyclohexyl (meth)acrylate,t-butylcyclohexyl (meth)acrylate, cyclododecyl (meth)acrylate andtricyclodecanyl (meth)acrylate; polymerizable unsaturated monomershaving isobornyl group, such as isobornyl (meth)acrylate; polymerizableunsaturated monomers having adamantyl group, such as adamantyl(meth)acrylate; polymerizable unsaturated monomers havingtricyclodecanyl group, such as tricyclodecanyl (meth)acrylate; aromaticring-containing polymerizable unsaturated monomers such as styrene,α-methylstyrene, vinyltoluene and benzyl (meth)acrylate; polymerizableunsaturated monomers having alkoxysilyl group, such asvinyltrimethoxysilane, vinyltriethoxysilane,vinyltris(2-methoxyethoxy)silane,γ-(meth)acryloyloxypropyltrimethoxysilane andγ-(meth)acryloyloxypropyltriethoxysilane; perfluoroalkyl (meth)acrylatessuch as perfluorobutylethyl (meth)acrylate and perfluorooctylethyl(meth)acrylate; polymerizable unsaturated monomers having fluorinatedalkyl group such as fluoroolefin; polymerizable unsaturated monomershaving photo-polymerizable functional group like maleimido group; vinylcompounds such as N-vinylpyrrolidone, ethylene, butadiene, chloroprene,vinyl propionate and vinyl acetate; monoesterified products of(meth)acrylic acid with C₂₋₈ dihydric alcohols such as 2-hydroxyethyl(meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl(meth)acrylate and 4-hydroxybutyl (meth)acrylate; these monoesterifiedproducts of (meth)acrylic acid with C₂₋₈ dihydric alcohols which aremodified with ε-caprolactone; hydroxyl-containing polymerizableunsaturated monomers such as N-hydroxymethyl (meth)acrylamide, allylalcohol and (meth)acrylate having hydroxyl-terminated polyoxyethylenechain; carboxyl-containing polymerizable unsaturated monomers such as(meth)acrylic acid, maleic acid, crotonic acid and β-carboxyethylacrylate; nitrogen-containing polymerizable unsaturated monomers such as(meth)acrylonitrile, (meth)acrylamide, N,N-dim ethylaminoethyl(meth)acrylate, N,N-diethylaminoethyl (meth)acrylate,N,N-dimethylaminopropyl (meth)acrylamide and addition products ofglycidyl (meth)acrylate with amines; epoxy-containing polymerizableunsaturated monomers such as glycidyl (meth)acrylate, β-methylglycidyl(meth)acrylate, 3,4-epoxycyclohexylmethyl (meth)acrylate,3,4-epoxycyclohexylethyl (meth)acrylate, 3,4-epoxycyclohexylpropyl(meth)acrylate and allylglycidyl ether; (meth)acrylates havingalkoxy-terminated polyoxyethylene chain. These monomers can be usedeither alone or in combination of two or more, according to theperformance required of the core-shell type water-dispersible,hydroxyl-containing acrylic resin.

Specific examples of the monomer (c-1) include, as aforesaid,monoesterified products of (meth)acrylic acid with C₂₋₈ dihydricalcohols, such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl(meth)acrylate, 3-hydroxypropyl (meth)acrylate and 4-hydroxybutyl(meth)acrylate; ε-caprolactone-modified products of the monoesterifiedproducts of (meth)acrylic acid with C₂₋₈ dihydric alcohols;N-hydroxymethyl (meth)acrylamide, allyl alcohol, and (meth)acrylatehaving polyoxyethylene chain of which molecular terminal is hydroxylgroup. These monomers can be used either alone or in combination of twoor more.

The use ratio of the monomer (c-1) preferably is within a range ofnormally 1-40 mass %, in particular, 4-25 mass %, inter alia, 7-19 mass%, based on the total mass of the monomers constituting the shell partcopolymer (II), for excellent stability of the core-shell typewater-dispersible acrylic resin in aqueous medium and water resistanceof the resulting coating film.

Monomer (c-4) which is used as a monomer for shell part copolymer (II)is a polymerizable unsaturated monomer containing at least C₆ straightor branched chain or cyclic saturated or unsaturated hydrocarbon group,excepting hydrophilic group-containing monomers such ashydroxyl-containing polymerizable unsaturated monomers. Examples of themonomer (c-4) include alkyl or cycloalkyl (meth)acrylates such asn-hexyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl(meth)acrylate, nonyl (meth)acrylate, tridecyl (meth)acrylate, lauryl(meth)acrylate, stearyl (meth)acrylate, “isostearyl acrylate”(tradename, Osaka Organic Chemical Industry Ltd.), cyclohexyl(meth)acrylate, methylcyclohexyl (meth)acrylate, t-butylcyclohexyl(meth)acrylate, cyclododecyl (meth)acrylate and tricyclodecanyl(meth)acrylate; polymerizable unsaturated monomers having isobornylgroup, such as isobornyl (meth)acrylate; polymerizable unsaturatedmonomers having adamantyl group, such as adamantyl (meth)acrylate;aromatic ring-containing polymerizable unsaturated monomers such asstyrene, α-methylstyrene, vinyltoluene and benzyl (meth)acrylate. Thesemonomers can be used either alone or in combination of two or more.

It is preferred to use as the monomer (c-4) a polymerizable unsaturatedmonomer having C₆₋₁₈ alkyl group and/or aromatic ring-containingpolymerizable unsaturated monomer, in particular, styrene, for improvingthe appearance of resulting coating film.

The use ratio of the monomer (c-4) is preferably within a range ofgenerally 5-60 mass %, in particular, 7-40 mass %, inter alia, 9-30 mass%, based on the total mass of the monomers constituting the shell partcopolymer (II), for excellent stability of the core-shell typewater-dispersible acrylic resin in aqueous medium and water resistanceof the resulting coating film.

When styrene is used as the monomer (c-4), the use ratio of styrene ispreferably within a range of generally 5-50 mass %, in particular, 7-30mass %, inter alia, 9-20 mass %, based on the total mass of the monomersconstituting the shell part copolymer (II).

Monomer (c-5) which is used as a monomer for the shell part copolymer(II) includes polymerizable unsaturated monomers other than the monomers(c-1) and (c-4), for example, alkyl or cycloalkyl (meth)acrylate such asmethyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate,i-propyl (meth)acrylate, n-butyl (meth)acrylate, i-butyl (meth)acrylateand tert-butyl (meth)acrylate; and carboxyl-containing polymerizableunsaturated monomers. These monomers can be used either alone or incombination of two or more.

As specific examples of the carboxyl-containing polymerizableunsaturated monomer, those named as the monomers for the above-describedcore part copolymer (I) can be named, acrylic acid and/or methacrylicacid being particularly preferred.

Use of the carboxyl-containing polymerizable unsaturated monomer as atleast a part of the monomer (c-5) allows to secure stability of theresulting core-shell type water-dispersible acrylic resin in aqueousmedium.

Where such a carboxyl-containing polymerizable unsaturated monomer isused, its use ratio is preferably within a range of normally 1-40 mass%, in particular, 6-25 mass %, inter alia, 7-19 mass %, based on thetotal mass of the monomers constituting the shell part copolymer (II),for excellent paint stability and water resistance of resulting coatingfilm.

Also from the viewpoint of improving appearance of the resulting coatingfilm, it is preferred not to use any polymerizable unsaturated monomerhaving at least two polymerizable unsaturated groups per molecule as themonomer (c-5) for constituting the shell part copolymer (II), to renderthe copolymer (II) uncrosslinked type.

The core-shell type water-dispersible acrylic resin (C1′) preferably hasa hydroxyl value within a range of generally 1-70 mgKOH/g, inparticular, 2-50 mgKOH/g, inter alia, 5-30 mgKOH/g, for excellent waterresistance of resulting coating film.

Furthermore, the core-shell type water-dispersible acrylic resin (C1′)preferably has an acid value within a range of generally 5-90 mgKOH/g,in particular, 8-50 mgKOH/g, inter alia, 10-35 mgKOH/g, from theviewpoint of storage stability of the paint composition and excellentwater resistance of resulting coating film.

The core-shell type water-dispersible acrylic resin (C1′) can beprepared, for example, by emulsion polymerizing a monomeric mixturecomposed of 0.1-30 mass % of monomer (c-2) and 70-99.9 mass % of monomer(c-3) to form an emulsion of the core part copolymer (I), thereafteradding into this emulsion a monomeric mixture composed of 1-35 mass % ofmonomer (c-1), 5-60 mass % of monomer (c-4) and 5-94 mass % of monomer(c-5), and further emulsion polymerizing the system to form the shellpart copolymer (II).

The emulsion polymerization for preparing an emulsion of the core partcopolymer (I) can be carried out by a method known Per se, for example,by emulsion polymerizing the monomeric mixture using a polymerizationinitiator, in the presence of an emulsifier.

As the emulsifier, anionic emulsifier or nonionic emulsifier aresuitable, examples of the anionic emulsifier including sodium salt orammonium salt of alkylsulfonic acid, alkylbenzenesulfonic acid,alkylphosphoric acid and the like. Examples of the nonionic emulsifierinclude polyoxyethylene oleyl ether, polyoxyethylene stearyl ether,polyoxyethylene lauryl ether, polyoxyethylene tridecyl ether,polyoxyethylene phenyl ether, polyoxyethylene nonylphenyl ether,polyoxyethylene octylphenyl ether, polyoxyethylene monolaurate,polyoxyethylene monostearate, polyoxyethylene monooleate, sorbitanmonolaurate, sorbitan monostearate, sorbitan trioleate andpolyoxyethylene sorbitan monolaurate.

Polyoxyalkylene-containing anionic emulsifier having an anionic groupand polyoxyalkylene group such as polyoxyethylene group orpolyoxypropylene group per molecule; or reactive anionic emulsifierhaving anionic group and radical-polymerizable unsaturated group permolecule, can also used as the emulsifier. Of these, use of reactiveanionic emulsifier is preferred.

As examples of the reactive anionic emulsifier, sodium salts or ammoniumsalts of sulfonic acid compounds having radical-polymerizableunsaturated groups such as (meth)allyl, (meth)acryloyl, propenyl,butenyl group and the like can be named. Because of excellent waterresistance of resulting coating film, ammonium salts of sulfonic acidcompounds having such radical-polymerizable unsaturated groups arepreferred among the above-named. As commercially available ammonium saltof such sulfonic acid compound, for example, LATEMUL S-180A (tradename,KAO Corporation) can be named.

Among the ammonium salts of sulfonic acid compounds having radicalpolymerizable unsaturated groups, those of sulfonic acid compoundshaving radical-polymerizable unsaturated group and polyoxyalkylene groupare preferred. As commercially available ammonium salt of sulfonic acidcompound having radical-polymerizable unsaturated group andpolyoxyalkylene group, for example, AQUALON KH-10 (tradename, Dai-ichiKogyo Seiyaku Co., Ltd.) and SR-1025A (tradename, ADEKA Corporation) canbe named.

Preferred use amount of such an emulsifier is, based on the total amountof all the monomers used, within a range of normally 0.1-15 mass %, inparticular, 0.5-10 mass %, inter alia, 1-5 mass %.

As the polymerization initiator, for example, organic peroxides such asbenzoyl peroxide, octanoyl peroxide, lauroyl peroxide, stearoylperoxide, cumene hydroperoxide, tert-butyl peroxide, tert-butylperoxylaurate, tert-butylperoxyisopropylcarbonate,tert-butylperoxyacetate and diisopropylbenzene hydroperoxide; azocompounds such as azobisisobutyronitrile,azobis(2,4-dimethylvaleronitrile), azobis(2-methylpropionitrile),azobis(2-methylbutyronitrile), 4,4′-azobis(4-cyanobutanoic acid),dimethylazobis(2-methylpropionate), azobis[2-methyl-N-(2-hydroxyethyl)-propionamide] andazobis{2-methyl-N-[2-(1-hydroxybutyl)]-propionamide}; and persulfatessuch as potassium persulfate, ammonium persulfate and sodium persulfatecan be named. These polymerization initiators can be used either aloneor in combination of two or more. Above polymerization initiators mayalso be used concurrently with such a reducing agent as sugar,sodiumformaldehyde sulfoxylate, iron complex or the like, to act asredox initiator.

The use amount of above polymerization initiator preferably is, based onthe total mass of all the monomers used, within a range of generally0.1-5 mass %, in particular, 0.2-3 mass %. Method of adding thepolymerization initiator is not particularly limitative, but can besuitably selected according to its kind, amount and the like. Forexample, it may be advancedly contained in the monomeric mixture oraqueous medium, or may be added in lump or added dropwise at the time ofpolymerization.

The core-shell type water-dispersible acrylic resin (C1′) can beobtained by adding a monomeric mixture composed of the above monomers(c-1), (c-4) and (c-5) to an emulsion of the core part copolymer (I) asobtained in the above, and further polymerizing to form the shell partcopolymer (II).

The monomeric mixture for making the shell part copolymer (II) cansuitably contain, where necessary, such components as aforedescribedpolymerization initiator, chain transfer agent, reducing agent,emulsifier and the like.

The monomeric mixture may be dropped as it is, but preferably it isdispersed in an aqueous medium to form a monomeric emulsified productand dropped. The particle size of the monomeric emulsified product inthat occasion is not particularly limited.

As the polymerization method of the monomeric mixture to form the shellpart copolymer (II), for example, a method of adding in lump or slowlydropwise, the monomeric mixture or the monomeric emulsified product toan emulsion of the core part copolymer (I), followed by heating thesystem to an adequate temperature under stirring, can be used.

Thus obtained core-shell type water-dispersible acrylic resin (C1′) hasa multilayer structure in which a copolymer (I) of a monomeric mixtureof the monomers (c-2) and (c-3) forms the core and a copolymer (II) of amonomeric mixture of the monomers (c-1), (c-4) and (c-5) forms theshell.

The core-shell type water-dispersible acrylic resin (C1′) can generallyhave an average particle size of about 10-1,000 nm, in particular, about20-500 nm.

In the present specification, the average particle diameter of thecore-shell type water-dispersible acrylic resin (C1′) is the valuemeasured with a submicron particle size distribution measuring deviceaccording to the customarily practiced method, as to the test specimenas diluted with deionized water, at 20° C. As the submicron particlesize distribution measuring device, for example, COULTER N4 Model(tradename, Beckman Coulter, Inc.) can be used.

With the view to improve mechanical stability of the core-shell typewater-dispersible acrylic resin (C1′) particles, it is desirable toneutralize the acidic groups such as carboxyl groups in thewater-dispersible acrylic resin (C1′) with a neutralizer. Theneutralizer is subject to no particular limitation so long as it canneutralize acidic groups and, for example, sodium hydroxide, potassiumhydroxide, trimethylamine, 2-(dimethylamino)ethanol,2-amino-2-methyl-1-propanol, triethylamine and aqueous ammonia can beused. These neutralizers are preferably used in an amount as will renderthe pH of an aqueous dispersion of the neutralized water-dispersibleacrylic resin around 6.5-9.0.

In the paint composition of the present invention, smoothness of coatingfilm formed therefrom can be improved by using hydroxy-containingpolyester resin (C2) as the hydroxyl-containing resin (C).

Hydroxyl-containing polyester resin (C2) can be usually prepared byesterification reaction or ester-interchange reaction of acid componentwith alcohol component.

As the acid component, those compounds customarily used as acidcomponent in production of polyester resins can be used, examples ofwhich including aliphatic polybasic acid, alicyclic polybasic acid andaromatic polybasic acid.

The aliphatic polybasic acid encompasses aliphatic compounds having atleast two carboxyl groups per molecule, acid anhydrides of the aliphaticcompounds and esterified products of the aliphatic compounds. Examplesof aliphatic polybasic acid include aliphatic polyvalent carboxylicacids such as succinic acid, glutaric acid, adipic acid, pimelic acid,suberic acid, azelaic acid, sebacic acid, undecanedioic acid,dodecanedioic acid, brassylic acid, octadecanedioic acid and citricacid; anhydrides of those aliphatic polyvalent carboxylic acids; andC₁₋₄ lower alkyl esters of those aliphatic polyvalent carboxylic acids.Those aliphatic polybasic acids can be used either alone or incombination of two or more. From the viewpoint of smoothness ofresulting coating film, use of adipic acid and/or adipic anhydride asthe aliphatic polybasic acid is particularly preferred.

The alicyclic polybasic acid generally encompasses compounds having atleast one alicyclic structure and at least two carboxyl groups permolecule, acid anhydrides of the compounds and esterified products ofthe compounds. The alicyclic structures are preferably mainly 4- to6-membered ring. Examples of alicyclic polybasic acids include alicyclicpolyvalent carboxylic acids such as 1,2-cyclohexanedicarboxylic acid,1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid,4-cyclohexene-1,2-dicarboxylic acid,3-methyl-1,2-cyclohexanedicarboxylic acid,4-methyl-1,2-cyclohexanedicarboxylic acid,1,2,4-cyclohexanetricarboxylic acid and 1,3,5-cyclohexanetricarboxylicacid; anhydrides of the alicyclic polyvalent carboxylic acids; and C₁₋₄lower alkyl esters of the alicyclic polyvalent carboxylic acids. Thosealicyclic polybasic acids can be used either alone or in combination oftwo or more. As the alicyclic polybasic acids, use of1,2-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic anhydride,1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid,4-cyclohexene-1,2-dicarboxylic acid and 4-cyclohexene-1,2-dicarboxylicanhydride is preferred from the viewpoint of smoothness of resultingcoating film. Of these, it is particularly preferred to use1,2-cyclohexanedicarboxylic acid and/or 1,2-cyclohexanedicarboxylicanhydride.

The aromatic polybasic acid generally include aromatic compounds havingat least two carboxyl groups per molecule, acid anhydrides of thearomatic compounds and esterified products of the aromatic compounds,for example, aromatic polyvalent carboxylic acid such as phthalic acid,isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid,4,4′-biphenyldicarboxylic acid, trimellitic acid and pyromellitic acid;anhydrides of those aromatic polyvalent carboxylic acids; and esterifiedproducts of those aromatic polyvalent carboxylic acids with C₁₋₄ loweralkyl can be named. Above aromatic polybasic acids can be used eitheralone or in combination of two or more. Those aromatic polybasic acidscan be used either alone or in combination of two or more. As thearomatic polybasic acid, use of phthalic acid, phthalic anhydride,isophthalic acid, trimellitic acid or trimellitic anhydride ispreferred.

Acid components other than the above aliphatic polybasic acid, alicyclicpolybasic acid and aromatic polybasic acid can also be used, without anyparticular limitation. For example, fatty acids such as coconut oilfatty acid, cottonseed oil fatty acid, hempseed oil fatty acid, ricebran oil fatty acid, fish oil fatty acid, tall oil fatty acid, soybeanoil fatty acid, linseed oil fatty acid, tung oil fatty acid, rape seedoil fatty acid, castor oil fatty acid, dehydrated castor oil fatty acidand safflower oil fatty acid; monocarboxylic acids such as lauric acid,myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid,linolenic acid, benzoic acid, p-tert-butylbenzoic acid, cyclohexanoicacid and 10-phenyloctadecanoic acid; and hydroxycarboxylic acids such aslactic acid, 3-hydroxybutanoic acid and 3-hydroxy-4-ethoxybenzoic acidcan be used. These acid components can be used either alone or incombination of two or more.

As the alcohol component, polyhydric alcohol having at least twohydroxyl groups per molecule can be conveniently used, examples of whichinclude dihydric alcohols such as ethylene glycol, propylene glycol,diethylene glycol, trimethylene glycol, tetraethylene glycol,triethylene glycol, dipropylene glycol, 1,4-butanediol, 1,3-butanediol,2,3-butanediol, 1,2-butanediol, 3-methyl-1,2-butanediol,2-butyl-2-ethyl-1,3-propanediol, 1,2-pentanediol, 1,5-pentanediol,1,4-pentanediol, 2,4-pentanediol, 2,3-dimethyltrimethylene glycol,tetramethylene glycol, 3-methyl-4,3-pentanediol,3-methyl-1,5-pentanediol, 2,2,4-trimethyl-1,3-pentanediol,1,6-hexanediol, 1,5-hexanediol, 1,4-hexanediol, 2,5-hexanediol,neopentyl glycol, 1,4-cyclohexanedimethanol, tricyclodecanedimethanol,hydrogenated bisphenol A and hydrogenated bisphenol F; polylactonediolsformed by adding lactones such as ε-caprolactone to these dihydricalcohols; ester diols such as bis(hydroxyethyl)terephthalate; polyetherdiols such as alkylene oxide adduct of bisphenol A, polyethylene glycol,polypropylene glycol and polybutylene glycol; tri- or higher-hydricalcohols such as glycerine, trimethylolethane, trimethylolpropane,diglycerine, triglycerine, 1,2,6-hexanetriol, pentaerythritol,dipentaerythritol, tris(2-hydroxyethyl)isocyanuric acid, sorbitol andmannitol; and polylactonepolyols formed by adding lactones such asε-caprolactone to these tri- or higher-hydric alcohols.

Alcohol component other than the above polyhydric alcohols can also beused without any particular limitation, examples of which includemonoalcohols such as methanol, ethanol, propyl alcohol, butyl alcohol,stearyl alcohol and 2-phenoxyethanol; and alcoholic compounds obtainedby reaction of monoepoxy compounds such as propylene oxide, butyleneoxide, CARDURA E10 (tradename, HEXION Specialty Chemicals Co., aglycidyl ester of synthetic highly branched saturated fatty acid) withacids.

Production method of hydroxyl-containing polyester resin (C2) is notcritical, but ordinary methods can be used. For example, suchhydroxyl-containing polyester resin can be prepared by heating theabove-described acid component and alcohol component in gaseous nitrogencurrent, at temperatures ranging about 150- about 250° C., for about5-10 hours to carry out an esterification reaction or ester-interchangereaction of the acid component with the alcohol component.

In the occasion of the esterification or ester-interchange reaction ofthe acid component with the alcohol component, they may be added to areactor all at once, or either one of them or both may be added asdivided portions. After synthesizing a hydroxyl-containing polyesterresin first, the resulting hydroxyl-containing polyester resin may bereacted with an acid anhydride to be half-esterified, whereby forming acarboxyl- and hydroxyl-containing polyester resin. Again, acarboxyl-containing polyester resin may be synthesized first, to whichthen above alcohol component is added to provide a hydroxyl-containingpolyester resin.

In the occasion of the esterification or ester-interchange reaction, perse known catalyst such as dibutyltin oxide, antimony trioxide, zincacetate, manganese acetate, cobalt acetate, calcium acetate, leadacetate, tetrabutyl titanate, tetraisopropyl titanate and the like maybe used for promoting the reaction.

The hydroxyl-containing polyester resin (C2) may also be modified,during or after preparation of the resin, with fatty acid, monoepoxycompound, polyisocyanate compound or the like. As the fatty acid, forexample, coconut oil fatty acid, cottonseed oil fatty acid, hempseed oilfatty acid, rice bran oil fatty acid, fish oil fatty acid, tall oilfatty acid, soybean oil fatty acid, linseed oil fatty acid, tung oilfatty acid, rape seed oil fatty acid, castor oil fatty acid, dehydratedcastor oil fatty acid and safflower oil fatty acid can be named; as themonoepoxy compound, for example, CARDURA E10 (tradename, HEXIONSpecialty Chemicals Co., a glycidyl ester of synthetic highly branchedsaturated fatty acid) can be favorably used; and as the polyisocyanatecompound, for example, aliphatic diisocyanates such as lysinediisocyanate, hexamethylene diisocyanate and trimethylhexanediisocyanate; alicyclic diisocyanates such as hydrogenated xylylenediisocyanate, isophorone diisocyanate,methylcyclohexane-2,4-diisocyanate, methylcyclohexane-2,6-diisocyanate,4,4′-methylenebis(cyclohexylisocyanate) and1,3-(isocyanatomethyl)cyclohexane; aromatic diisocyanates such astolylene diisocyanate, xylylene diisocyanate and diphenylmethanediisocyanate; organic polyisocyanates themselves such as tri- orhigher-valent polyisocyanates like lysine triisocyanate; adducts of eachof these organic polyisocyanates with polyhydric alcohol, low molecularweight polyester resin, water or the like; cyclized polymers betweeneach of these organic polyisocyanates (e.g., isocyanurates) and biurettype adducts can be named. These polyisocyanate compounds can be usedeither alone or in combination of two or more.

In the hydroxyl-containing polyester resin (C2), preferably the contentof alicyclic polybasic acid in the starting acid component lies within arange of generally 20-100 mol %, in particular, 25-95 mol %, inter alia,30-90 mol %, based on the total amount of the acid component, from theviewpoint of excellent appearance of resulting coating film.Particularly for excellent smoothness of the coating film,1,2-cyclohexanedicarboxylic acid and/or 1,2-cyclohexane-dicarboxylicanhydride are preferred as the alicyclic polybasic acid.

The hydroxyl-containing polyester resin (C2) preferably has a hydroxylvalue within a range of generally 10-200 mgKOH/g, in particular, 20-180mgKOH/g, inter alia, 30-160 mgKOH/g. Where the hydroxyl-containingpolyester resin (C2) has carboxyl groups, it preferably has an acidvalue within a range of generally 5-150 mgKOH/g, in particular, 10-100mgKOH/g, inter alia, 20-70 mgKOH/g. Furthermore, the hydroxyl-containingpolyester resin (C2) preferably has a weight-average molecular weightwithin a range of generally 500-100,000, in particular, 1,000-50,000,inter alia, 1,500-20,000.

The blend ratio of the hydroxyl-containing resin (C) in the paintcomposition of the present invention is, based on the combined amount ofthe hydroxyl-containing resin (C) and later described curing agent (D),preferably within a range of generally 30-95 mass %, in particular,50-90 mass %, inter alia, 60-80 mass %.

In particular, when the paint composition of the present inventioncontains hydroxyl-containing acrylic resin (C1) as thehydroxyl-containing resin (C), the blend ratio of thehydroxyl-containing acrylic resin (C1) preferably is within a range ofgenerally 2-70 mass %, in particular, 10-55 mass %, inter alia, 20-45mass %, based on the combined amount of the hydroxyl-containing resin(C) and curing agent (D).

Also when the paint composition of the present invention containshydroxyl-containing polyester resin (C2) as the hydroxyl-containingresin (C), the blend ratio of the hydroxyl containing polyester resin(C2) preferably is within a range of generally 2-70 mass %, inparticular, 5-55 mass %, inter alia, 10-45 mass %, based on the combinedamount of the hydroxyl-containing resin (C) and curing agent (D).

As the curing agent (D), compounds which are reactable withcrosslinkable functional groups in the base resin, such as hydroxyl,carboxyl, epoxy and the like, can be used, for example, amino resin(D1), polyisocyanate compound (D1), blocked polyisocyanate compound(D3), epoxy-containing compound, carboxyl-containing compound andcarbodiimido-containing compound, which can be used either alone or incombination of two or more. Of these, amino resin (D1), polyisocyanatecompound (D2) and blocked polyisocyanate compound (D3) which arereactable with hydroxyl group; and carbodiimido-containing compoundwhich is reactable with carboxyl group, in particular, amino resin (D1),polyisocyanate compound (D2) and blocked polyisocyanate compound (D3)are suitable.

When the paint composition of the invention is water-based, itpreferably contains as the curing agent (D) amino resin (D1) and/orblocked polyisocyanate compound (D3), and when the paint composition ofthe invention is organic solvent-based, it preferably contains as thecuring agent (D) amino resin (D1) and/or polyisocyanate compound (D2).

Examples of the amino resin (D1) include partially or completelymethylolated amino resins obtained through reaction of such aminocomponent as melamine, urea, benzoguanamine, acetoguanamine,steroguanamine, spiroguanamine or dicyandiamide with aldehyde. As thealdehyde, formaldehyde, paraformaldehyde, acetaldehyde, benzaldehyde andthe like can be named. Also these methylolated amino resins whosemethylol groups are partially or completely etherified with suitablealcohol can also be used, examples of the alcohol used for theetherification including methyl alcohol, ethyl alcohol, n-propylalcohol, i-propyl alcohol, n-butyl alcohol, i-butyl alcohol,2-ethylbutanol and 2-ethylhexanol.

As the amino resin (D1), melamine resins are preferred, in particular,methyl etherified melamine resins, formed by partially or completelyetherifying methylol groups in partially or completely methylolatedmelamine resins, with methyl alcohol; butyl etherified melamine resinsformed by partially or completely etherifying methylol groups inpartially or completely methylolated melamine resins, with butylalcohol; and methyl-butyl mixed etherified melamine resins formed bypartially or completely etherifying methylol groups of partially orcompletely methylolated melamine resins, with methyl alcohol and butylalcohol; are preferred.

The melamine resin (D1) preferably has a weight-average molecular weightwithin a range of normally 400-5,000, in particular, 600-4,000, interalia, 1,000-3,000.

As commercially available melamine resin (D1), for example, CYMEL 202,CYMEL 203, CYMEL 238, CYMEL 251, CYMEL 303, CYMEL 323, CYMEL 324, CYMEL325, CYMEL 327, CYMEL 350, CYMEL 385, CYMEL 1156, CYMEL 1158, CYMEL 1116and CYMEL 1130 (tradename, Nippon Cytec Industries, Inc.); U-VAN 120,U-VAN 20HS, U-VAN 20SE60, U-VAN 2021, U-VAN 2028 and U-VAN-28-60(tradename, Mitsui Chemical Inc.) can be used.

Such melamine resins (D1) can be used either alone or in combination oftwo or more.

The polyisocyanate compound (D2) is a compound containing at least twoisocyanate groups per molecule, examples of which include aliphaticpolyisocyanates such as hexamethylene diisocyanate,trimethylhexamethylene diisocyanate, dimeric acid diisocyanate andlysine diisocyanate; and biuret type adducts and isocyanurate ringadducts of these polyisocyanates; alicyclic diisocyanates such asisophorone diisocyanate, 4,4′-methylenebis(cyclohexyl isocyanate),methylcyclohexane-2,4-diisocyanate, methylcyclohexane-2,6-diisocyanate,1,3-di(isocyanatomethyl)cyclohexane,1,4-di(isocyanatomethyl)-cyclohexane, 1,4-cyclohexane diisocyanate,1,3-cyclopentane diisocyanate and 1,2-cyclohexane diisocyanate; andbiuret type adducts and isocyanurate ring adducts of thesepolyisocyanates; aromatic diisocyanate compounds such as xylylenediisocyanate, metaxylylene diisocyanate, tetramethylxylylenediisocyanate, tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate,1,5-naphthalene diisocyanate, 1,4-naphthalene diisocyanate,4,4′-toluidine diisocyanate, 4,4′-diphenyl ether diisocyanate,m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4′-biphenylenediisocyanate, 3,3′-dimethyl-4,4′-biphenylene diisocyanate,bis(4-isocyanatophenyl)-sulfone and isopropylidene-bis(4-phenylisocyanate); and biuret type adducts and isocyanurate ring adducts ofthese polyisocyanates; polyisocyanates having at least three isocyanategroups per molecule, such as triphenylmethane-4,4′,4″-triisocyanate,1,3,5-triisocyanatobenzene, 2,4,6-triisocyanatotoluene and4,4′-dimethyldiphenylmethane-2,2′,5,5′-tetraisocyanate; and biuret typeadducts and isocyanurate ring adducts of these polyisocyanates;urethanated adducts formed by reacting with hydroxyl groups of polyolssuch as ethylene glycol, propylene glycol, 1,4-butylene glycol,dimethylolpropionic acid, polyalkylene glycol, trimethylolpropane andhexanetriol, polyisocyanate compounds at a ratio to render theisocyanate groups excessive; and biuret type adducts and isocyanuratering adducts of these polyisocyanates.

Blocked polyisocyanate compounds (D3) are usually obtained by adding ablocking agent to isocyanate groups of above polyisocyanate compounds(D2), from which the blocking agent dissociates when heated, toregenerate the isocyanate groups which can react with hydroxyl groupsand the like. The dissociation temperature of such blocking agentpreferably ranges 60-160° C., in particular, 70-140° C.

Examples of the blocking agent include phenols such as phenol, cresol,xylenol, nitrophenol, ethylphenol, hydroxydiphenyl, butylphenol,isopropylphenol, nonylphenol, octylphenol, methyl hydroxybenzoate andthe like; lactams such as ε-caprolactam, δ-valerolactam, γ-butyrolactam,α-propiolactam and the like; aliphatic alcohols such as methanol,ethanol, propyl alcohol, butyl alcohol, amyl alcohol, lauryl alcohol andthe like; ethers such as ethylene glycol monomethyl ether, ethyleneglycol monoethyl ether, ethylene glycol monobutyl ether, diethyleneglycol monomethyl ether, diethylene glycol monoethyl ether, propyleneglycol monomethyl ether, methoxymethanol and the like; alcohols such asbenzyl alcohol, glycolic acid, methyl glycolate, ethyl glycolate, butylglycolate, lactic acid, methyl lactate, ethyl lactate, butyl lactate,methylolurea, methylolmelamine, diacetone alcohol, 2-hydroxyethylacrylate, 2-hydroxyethyl methacrylate and the like; oximes such asformamidoxime, acetamidoxime, acetoxime, methyl ethyl ketoxime,diacetylmonooxime, benzophenone-oxime, cyclohexane-oxime and the like;active methylenes such as dimethyl malonate, diethyl malonate, ethylacetoacetate, methyl acetoacetate, acetylacetone and the like;mercaptans such as butyl mercaptan, t-butyl mercaptan, hexyl mercaptan,t-dodecyl mercaptan, 2-mercaptobenzothiazole, thiophenol,methylthiophenyl, ethylthiophenol and the like; acid amides such asacetanilide, acetanisidide, acetotoluide, acrylamide, methacrylamide,acetic acid amide, stearic acid amide, benzamide and the like; imidessuch as succinimide, phthalimide, maleimide and the like; amines such asdiphenylamine, phenylnaphthylamine, xylidine, N-phenylxylidine,carbazole, aniline, naphthylamine, butylamine, dibutylamine,butylphenylamine and the like; imidazoles such as imidazole,2-ethylimidazole and the like; ureas such as urea, thiourea,ethyleneurea, ethylenethiourea, diphenylurea and the like; carbamic acidesters such as phenyl N-phenylcarbamate; imines such as ethyleneimine,propyleneimine and the like; sulfurous acid salts such as sodiumdisulfite, potassium disulfite and the like; and azole compounds. As theazole compounds, pyrazole or pyrazole derivatives, such as pyrazole,3,51-dimethylpyrazole, 3-methylpyrazole, 4-benzyl-3,5-dimethylpyrazole,4-nitro-3,5-dimethylpyrazole, 4-bromo-3,5-dimethylpyrazole,3-methyl-5-phenylpyrazole and the like; imidazole or imidazolederivatives such as imidazole, benzimidazole, 2-methylimidazole,2-ethylimidazole, 2-phenylimidazole and the like; and imidazolinederivatives such as 2-methylimidazoline, 2-phenylimidazoline and thelike can be named. As preferred blocking agent, oxime blocking agent,active methylene blocking agent, pyrazole or pyrazole derivatives can beused.

As the blocking agent, also hydroxycarboxylic acid having at least oneeach of hydroxyl group and carboxyl group, such as hydroxypivalic acid,dimethylolpropionic acid and the like can be used. Particularly when thepaint composition of this invention is water-based, blockedpolyisocyanate compound to which water dispersibility is imparted byblocking its isocyanate groups with above hydroxycarboxylic acid andneutralizing the carboxyl groups of the hydroxycarboxylic acid can befavorably used.

The use ratios among the pigment-dispersing resin (A), pigment (B),hydroxyl-containing resin (C) and curing agent (D) in the paintcompositions of the present invention are not strictly limited. Ingeneral terms, however, they may be within the following ranges, per 100mass parts of total solid resin content of the hydroxyl-containing resin(C) and the curing agent (D):

-   Pigment-dispersing resin (A): 0.5-30 mass parts, preferably 1-20    mass parts, inter alia, 2-10 mass parts,-   Pigment (B): 2-70 mass parts, preferably 5-50 mass parts, inter    alia, 8-40 mass parts,-   Hydroxyl-containing resin (C): 40-90 mass parts, preferably 50-85    mass parts, inter alia, 60-80 mass parts.-   Curing agent (D): 10-60 mass parts, preferably 15-50 mass parts,    inter alia, 20-40 mass parts.

As the solvent used in the paint compositions of the present inventionwhere necessary, water and/or organic solvent can be named. As theorganic solvent, for example, those organic solvents as explained asbeing useful for producing the pigment dispersions, where necessary, canbe used. In particular, water and hydrophobic solvent (E) are preferablycontained as the solvent, when the paint compositions of the presentinvention are water-based.

The hydrophobic solvent (E) in the present invention is an organicsolvent whose mass soluble in 100 g of 20° C. water is not more than 10g, preferably not more than 5 g, inter alia, not more than 1 g. Examplesof such solvent include hydrocarbon solvents such as rubber gasoline,mineral spirit, toluol, xylol and solvent naphtha; alcohol solvents suchas 1-hexanol, 1-octanol, 2-octanol, 2-ethylhexanol, 1-decanol, benzylalcohol, ethylene glycol mono-2-ethylhexyl ether, propylene glycolmono-n-butyl ether, dipropylene glycol mono-n-butyl ether, tripropyleneglycol mono-n-butyl ether, propylene glycol mono-2-ethylhexyl ether andpropylene glycol monophenyl ether; ester solvents such as n-butylacetate, isobutyl acetate, isoamyl acetate, methylamyl acetate andethylene glycol monobutyl ether acetate; and ketone solvents such asmethyl isobutyl ketone, cyclohexanone, ethyl n-amyl ketone anddiisobutyl ketone. These can be used either alone or in combination oftwo or more.

Of those, from the viewpoint of excellent appearance of resultingcoating film, the hydrophobic solvent (E) is preferably an alcoholsolvent, in particular C₇₋₁₄ alcohol solvent, for example, 1-octanol,2-octanol, 2-ethyl-1-hexanol, ethylene glycol mono-2-ethylhexyl ether,propylene glycol mono-n-butyl ether and dipropylene glycol mono-n-butylether, can be favorably used.

Also when paint compositions of the present invention contain suchhydrophobic solvent (E), the blend amount of the hydrophobic solvent (E)is preferably within a range of usually 2-70 mass parts, in particular,11-60 mass parts, inter alia, 16-50 mass parts, per 100 mass parts ofthe combined solid content of the hydroxyl-containing resin (C) andcuring agent (D) in the paint composition of the invention.

As the curing catalyst, when amino resin (D1) such as melamine resin isused as the curing agent (D), for example, sulfonic acid compound suchas paratoluenesulfonic acid, dodecylbenzenesulfonic acid,dinonylnaphthalenesulfonic acid and the like, or amine-neutralizedproducts of these sulfonic acids can be favorably used. Wherepolyisocyanate compound (D2) and/or blocked polyisocyanate compound (D3)are used as the curing agent (D), for example, organometal catalyst suchas dibutyltin diacetate, dibutyltin dioctate, dibutyltin dilaurate andthe like; and amines such as triethylamine, diethanolamine and the likecan be favorably used.

Where paint compositions of the invention contains such curing catalyst,the blend amount of the curing catalyst is preferably within a range ofusually 0.001-10 mass parts, in particular, 0.01-5 mass parts, interalia, 0.05-2 mass parts, per 100 mass parts of the combined solidcontent of the hydroxyl-containing resin (C) and curing agent (D) in thepaint composition of the invention.

The fine polymer particles are of a polymer which is not dissolved inpaint compositions of the invention but is dispersed in the form of fineparticles. Those having an average particle size within a range ofnormally 0.01-1 μm, in particular, 0.05-0.8 μm are preferred. While thefine polymer particles may or may not be internally crosslinked,internally crosslinked particles are preferred. As the fine polymerparticles, for example, those per se known in the paint field as paintfluidity-regulating agent can be used.

As the ultraviolet absorber, for example, benzophenone, benzotriazole,cyanoacrylate, salicylate and anilide oxalate compounds can be named,and as the light stabilizer, for example, hindered amine compounds canbe named.

As the thickener, for example, inorganic thickeners such as silicate,metal silicate, montmorillonite, organic montmorillonite and colloidalalumina; polyacrylic acid-derived thickeners such as copolymers ofpolyacrylic acid with (meth)acrylic acid esters and sodium polyacrylate;association type thickeners having hydrophilic moiety and hydrophobicmoiety per molecules, which exhibit effective thickening action as thehydrophobic moiety is adsorbed onto surfaces of pigment or emulsionparticles in the composition, or the hydrophobic moieties mutuallyassociate; cellulose derivatives-derived thickeners such ascarboxymethyl cellulose, methyl cellulose and hydroxyethyl cellulose;protein-derived thickeners such as casein, sodium caseinate and ammoniumcaseinate; alginic acid-derived thickeners such as sodium alginate;polyvinyl-derived thickeners such as polyvinyl alcohol,polyvinylpyrrolidone and polyvinylbenzyl ether copolymer;polyether-derived thickeners such as polyether dialkyl ester, polyetherdialkyl ether and polyether epoxy-modified product; maleic anhydridecopolymer-derived thickeners such as partial esters of vinylmethylether-maleic anhydride copolymers; and polyamide-derived thickeners suchas polyamide amine salts can be named. These thickeners can be usedeither alone or in combination of two or more.

Examples of commercially available polyacrylic acid-derived thickenersinclude PRIMAL ACE-60, PRIMAL TT-615 and PRIMAL RM-5 (tradename, Rhom &Haas Company); SN Thickener 613, SN Thickener 618, SN Thickener 630, SNThickener 634 and SN Thickener 636 (tradename, SAN NOPCO, Ltd.).

Examples of commercially available association type thickener includeUH-420, UH-450, UH-462, UH-472, UH-540, UH-752, UH-756VF and UH-814N(tradename, ADEKA Corporation); PRIMAL RM-8W, PRIMAL RM-825, PRIMALRM-2020 NPR, PRIMAL RM-12W and PRIMAL SCT-275 (tradename, Rhom & HaasCompany); and SN Thickener 612, SN Thickener 621N, SN Thickener 625N, SNThickener 627N and SN Thickener 660T (tradename, SAN NOPCO, Ltd.).

According to the invention, use of those polyacrylic acid-derivedthickener and/or association type thickener as the thickener ispreferred, in particular, association type thickener being preferred. Itis even more advantageous to use urethane association type thickenerhaving terminal hydrophobic group and at least one urethane bond in themolecular chain. Examples of commercially available urethane associationtype thickener that are particularly preferred include UH-420, UH-462,UH-472, UH-540, UH-756 VF, UH-814N, SN Thickener 612, SN Thickener 621N,SN Thickener 625N, SN Thickener 627N and SN Thickener 660T (tradenames,all manufactured by ADEKA Corporation).

When paint compositions of the present invention contain abovethickeners, the content of the thickener in a composition of theinvention is preferably within a range of usually 0.01-10 mass parts, inparticular, 0.05-3 mass parts, inter alia, 0.1-2 mass parts, per 100mass parts in total of the hydroxy-containing resin (C) and curing agent(D). Also when the above association type thickener is contained as thethickener, its content in the composition preferably is within a rangeof usually 0.01-10 mass parts, in particular, 0.05-2 mass parts, interalia, 0.1-1 mass part, per 100 mass parts in total of the hydroxylcontaining resin (C) and curing agent (D).

Coating Object

Objects which can be coated with the paint compositions of the presentinvention is subject to no particular limitation and, for example, outerpanels of car bodies such as of automobiles, trucks, motorcycles andbuses; car parts; outer panels of household appliances such as mobilephones and audio instruments can be named. Of those, outer panels of carbodies and car parts are suitable.

Materials of such coating objects are not particularly limited. Forexample, metallic materials such as iron, aluminium, brass, copper,stainless steel, tin plate, zinc-plated steel, alloyed zinc (Zn—Al,Zn—Ni, Zn—Fe and the like), and plated steel; plastic materials such asresins, e.g., polyethylene resin, polypropylene resin,acrylonitrile-butadiene-styrene (ABS) resin, polyamide resin, acrylicresin, vinylidene chloride resin, polycarbonate resin, polyurethaneresin and epoxy resin, and various FRP's; inorganic materials such asglass, cement and concrete; wood; and fibrous materials (paper, clothand the like) can be used. Of those, metallic materials and plasticmaterials are preferred.

Above coating objects may be metallic materials or metallic surfacessuch as of car bodies made thereof, onto which surface treatment such asphosphate treatment, chromate treatment, complex oxide treatment or thelike has been given, or coating film has been further formed thereon.

As such film-coated objects, those formed by surface treating substratesand applying undercoat thereon; or by further applying on the undercoatan intermediate coat; can be used.

Paint compositions of the present invention can form coating film ofexcellent appearance and water resistance, and hence can be favorablyused as top coat paint for automobiles.

When a paint composition of the present invention is used as a top coatpaint for automobiles, typical examples of the objects to be coated arechemical conversion treated sheet steel on which undercoat is formed byelectrocoating and further an intermediate paint is applied on theundercoat where necessary; various plastic materials (where necessary,advancedly surface-treated, primer-coated and intermediate coated); andcomposite materials which are combination of the foregoing.

As the paint used for the above electrocoating, either of anionicelectrodeposition paint and cationic electrodeposition paint can beused, while cationic electrodeposition paint exhibiting good corrosionresistance is desirable. As the cationic electrodeposition paint, thoseknown per se can be used, for example, one containing base resin havinghydroxyl groups and cationic groups and curing agent such as blockedpolyisocyanate compound as the resin component can be conveniently used.

Also as the intermediate paint, thermosetting type intermediate paintknown per se can be used, specific examples including such paintscomprising base resins such as alkyd resin, polyester resin, acrylicresin, urethane resin and the like, in suitable combination with curingagents such as amino resin, polyisocyanate compound, blockedpolyisocyanate compound and the like which contain the groups reactablewith the reactive functional groups contained in the base resins. As theintermediate paint, high-solid paint, water-based paint or powder paintusing less organic solvent are preferred, from the viewpoint ofenvironmental preservation and source saving.

Coating Method

Method for coating such objects as above-described with paintcompositions of the present invention is subject to no particularlimitation and, for example, air spray coating, airless spray coating,rotary atomizing coating, curtain flow coating and the like may be used.Wet coating films can be formed by these means. These coating methodsmay be practiced under impression of static electricity, wherenecessary, and rotary atomizing system electrostatic coating and airspray system electrostatic coating are preferred, the former beingparticularly preferred. The use amount of a paint composition of thepresent invention is variable depending on, e.g., intended utility ofthe coated object, while such an amount as will make the cured filmthickness normally 5-50 μm, in particular, 8-40 μm, inter alia, 10-30μm, is preferred.

Curing of wet coating film can be effected by heating after applying apaint composition of the present invention onto a coating object.Heating can be given by per se known heating means, for example, dryingoven such as hot air oven, electric oven or infrared ray inductionheating oven. Suitable heating temperature normally ranges 80-180° C.,preferably 100-160° C. While the heating time is not critical, it can benormally around 20-40 minutes.

Paint compositions of the present invention can be favorably used aspaints for automobiles, in particular, as base coat paint in a coatingmethod in which the object is applied with a base coat paint containingeffect pigment and/or coloring pigment and then applied with a clearpaint.

In the occasions of using the paint compositions of the presentinvention as the base coat paint, for example, a paint composition ofthe invention is applied onto an electrocoated and/or intermediatecoated object and, without curing the formed coating film, a clear paintis applied onto the uncured coating film, followed by curing the uncuredcoating film and the clear coating film simultaneously by heating. Usingsuch 2-coat-1-bake system, multilayer coating film can be formed. The“uncured coating film” includes set-to-touch film and dry-to-touch film.

In case of applying a paint composition of the present invention by2-coat-1-bake system, the composition is suitably coated to provide adry film thickness within a range of normally 5-40 μm, in particular,10-30 μm, inter alia, 10-20 μm; and the clear paint is suitably appliedto a dry film thickness within a range of normally 10-80 μm, inparticular, 15-60 μm. When the paint composition of the invention iswater-based, preferably the composition after application is preheatedunder such heating condition as will not substantially cure the coatingfilm, for prevention of occurrence of defect in coating film such ascissing. The preheating temperature normally ranges roomtemperature—100° C., preferably 40-90° C., and the preheating time canrange normally 30 seconds—15 minutes, preferably 1-5 minutes.Furthermore, after applying the clear paint, an interval at roomtemperature of normally 1-60 minutes, preferably 3-20 minutes, may betaken or preheating at about 40-80° C. for 1-60 minutes may be given,where necessary.

Curing of the paint composition of the invention and the clear paint canbe effected by heating means known per se as aforesaid. Specifically,for example, it is suitable to simultaneously cure the two films, byheating at temperatures of normally about 80- about 180° C., preferablyabout 100- about 160° C., for around 10-40 minutes.

It is also possible to form multilayer coating film by 3-coat-1-bakesystem, in which an intermediate paint is applied onto an object;without curing the formed coating film a coating composition of thepresent invention as a base coat paint is applied onto the uncuredintermediate coating film; without curing the formed coating film aclear paint is applied onto the uncured base coating film, to form aclear coating film; and the three layers of the intermediate coatingfilm, base coating film and clear coating film are simultaneously curedby heating.

As the clear paint, those known per se, which are customarily used, forexample, for coating automobile bodies, can be used. Specifically, forexample, organic solvent-based thermosetting paint, water-basedthermosetting paint, thermosetting powder paint, thermosetting waterdispersion liquid (slurry) paint and the like can be named, whichcontain as resin component a base resin such as acrylic resin, polyesterresin, alkyd resin, urethane resin, epoxy resin, fluorine-containingresin and the like, having crosslinkable functional groups such ashydroxyl, carboxyl, epoxy and silanol groups; and crosslinking agentsuch as melamine resin, urea resin, optionally blocked polyisocyanatecompound, carboxyl-containing compound or resin, epoxy-containingcompound or resin. Of these, thermosetting paint comprisinghydroxyl-containing resin and melamine resin, thermosetting paintcomprising carboxyl-containing resin and epoxy-containing resin, andthermosetting paint comprising hydroxyl-containing resin and optionallyblocked polyisocyanate compound, are preferred.

Desirable blend ratio of the base resin and crosslinking agent is suchthat the base resin component is normally 50-90 mass %, in particular,60-80 mass %, and the crosslinking agent component, normally 20-40 mass%, based on the sum of the two components.

The clear paint may be one-package type or may be two-package type liketwo-package type urethane resin paint.

The clear paint may also contain, where necessary, coloring pigment,effect pigment, dye and the like to an extent not interfering withtransparency of the paint, and furthermore can suitably containextender, ultraviolet absorber, light stabilizer, defoamer, thickener,rust proofing agent, surface regulating agent and the like.

EXAMPLES

Hereinafter the invention is explained more specifically, referring toworking Examples and Comparative Examples, it being understood that theinvention is not limited to these Examples only. “Part” and “%”appearing hereafter are invariably by mass.

Production of Polymerizable Unsaturated Monomer (m-6) Having DivalentGroup Represented by the General Formula (I) and Phosphoric Acid Group

Production Example 1

A reactor was charged with 358 parts of PLACCEL FM2D (tradename, DaicelChemical Industries, Ltd., a monomer formed by adding 2 mols ofε-caprolactone per mol of 2-hydroxyethyl methacrylate) and into which63.9 parts of phosphorus pentoxide was added little by little at 50-60°C., while introducing dry air into the reaction liquid by bubbling.After completion of the addition, the reaction system was aged at 60° C.for 5 hours, followed by addition of 9.0 parts of deionized water.Further aging the system at 80° C. for 5 hours, polymerizableunsaturated monomer (m-6-1) was obtained.

Production Example 2

A reactor was charged with 244 parts of PLACCEL FM1 (tradename, DaicelChemical Industries, Ltd., a monomer formed by adding 1 mol ofε-caprolactone per mol of 2-hydroxyethyl methacrylate), 1.44 parts ofstannic chloride and 0.18 part of hydroquinone monomethyl ether (MEHQ).After substituting the inside space of the reactor with nitrogen, 116parts of propylene oxide was introduced under elevated pressure whilethe temperature was maintained at no higher than 40° C., followed by anhour's aging.

Successively, 63.9 parts of phosphorus pentoxide was added little bylittle at 50-60° C., while introducing dry air into the reaction liquidby bubbling. After completion of the addition, the reaction system wasaged at 60° C. for 5 hours, followed by addition of 9.0 parts ofion-exchange water. Further aging the system at 80° C. for 5 hours,polymerizable unsaturated monomer (m-6-2) was obtained.

Production Example 3

A reactor was charged with 398 parts of BLENMER PE-200 (tradename, NOFCorporation, polyethylene glycol monomethacrylate), 114 parts ofε-caprolactone, 0.008 part of monobutyltin oxide 0.3 part of MEHQ, andtemperature-raising was started while introducing dry air into thereaction liquid by bubbling. The reaction temperature was maintainedconstantly at 120° C. The content in the reactor was sampled, whereby toquantitate the amount of unreacted ε-caprolactone by means of gaschromatograph, and the reaction mixture was cooled when the conversionexceeded 95%.

Successively, 63.9 parts of phosphorus pentoxide was added little bylittle at 50-60° C. After completion of the addition, the reactionsystem was aged at 60° C. for 5 hours, followed by addition of 9.0 partsof deionized water. Further aging the system at 80° C. for 5 hours,polymerizable unsaturated monomer (m-6-3) was obtained.

Production Example 4

A reactor was charged with 115 parts of HEAA (tradename, KOHJIN Co.,Ltd., N-hydroxyethylacrylamide), 228 parts of ε-caprolactone, 0.00686part of monobutyltin oxide and 0.258 part of MEHQ, andtemperature-raising was started while introducing dry air into thereaction liquid by bubbling. The reaction temperature was maintainedconstantly at 120° C. The content in the reactor was sampled, whereby toquantitate the amount of unreacted ε-caprolactone by means of gaschromatograph, and the reaction mixture was cooled when the conversionexceeded 95%.

Successively, 63.9 parts of phosphorus pentoxide was added little bylittle at 50-60° C., while introducing dry air into the reaction liquidby bubbling. After completion of the addition, the reaction system wasaged at 60° C. for 5 hours, followed by addition of 9.0 parts ofdeionized water. Further aging the system at 80° C. for 5 hours,polymerizable unsaturated monomer (m-6-4) was obtained.

Production of Polymerizable Unsaturated Monomer (m-8) having DivalentGroup Represented by the General Formula (I) and Sulfonic Acid Group

Production Example 5

A reactor was charged with 358 parts of PLACCEL FM2D (tradename, DaicelChemical Industries, Ltd., a monomer formed by adding 2 mols ofε-caprolactone per mol of 2-hydroxyethyl methacrylate), which wasreacted with 115 parts of methanesulfonyl chloride in the concurrentpresence of pyridine at 0° C. for 10 hours, while introducing dry airinto the reaction liquid by bubbling. The resulting mixture was washedwith water. Then 1,000 parts of 40% aqueous sodium sulfite solution wasadded and violently stirred to cause their reaction, followed byneutralization with sulfuric acid. The resulting mixture was washed withwater to provide polymerizable unsaturated monomer (m-8-1).

Production of Pigment-dispersing Resin (A)

Example 1

A reactor equipped with a thermometer, thermostat, stirrer, refluxcondenser, nitrogen inlet pipe and dropping device was charged with 120parts of dipropylene glycol dimethyl ether (which contained no hydroxylgroup and had a solubility in 20° C. water of 100 mass % or more), whichwas heated to 110° C. While maintaining the same temperature, 106 partsof a monomeric mixture composed of 30 parts of PLACCEL FM2D (tradename,Daicel Chemical Industries, Ltd., a monomer formed by adding 2 mols ofε-caprolactone per mol of 2-hydroxyethyl methacrylate), 10 parts ofLight Ester P-1M (tradename, Kyoeisha Chemical Co., acid phosphoxyethylmethacrylate), 30 parts of styrene, 30 parts of cyclohexyl methacrylateand 6 parts of t-butyl peroxy-2-ethylhexanoate was dropped into thereactor, consuming 4 hours, followed by an hour's aging under stirring.Thereafter a polymerization initiator solution composed of 1 part oft-butyl peroxy-2-ethylhexanoate and 30 parts of dipropylene glycoldimethyl ether was added dropwise over an hour, followed by an hour'saging under stirring. Thus a pigment-dispersing resin solution (A-1)having a solid concentration of 39% was obtained. The resultingpigment-dispersing resin had an acid value of 125 mgKOH/g, hydroxylvalue of 45 mgKOH/g and a number-average molecular weight of 20,000.

Examples 2-19, Comparative Examples 1-4

Example 1 was repeated except that the blend ratios were changed tothose as shown in the following Table 1, to produce pigment-dispersingresin solutions each having a solid concentration of 39%, (A-2) to(A-23). The acid value, hydroxyl value and number-average molecularweight of resulting pigment-dispersing resin solutions (A-2) to (A-23)are shown in the following Table 1, concurrently with those values ofthe pigment-dispersing resin solution (A-1) of Example 1. In the Table1, the amount of each of the polymerizable unsaturated monomer is thatof the solid content.

TABLE 1 Example 1 2 3 4 5 6 7 8 9 10 11 12 Pigment-dispersing resinsolution A-1 A-2 A-3 A-4 A-5 A-6 A-7 A-8 A-9 A-10 A-11 A-12 Dipropyleneglycol dimethyl ether 120 N-methyl-2-pyrrolidone (note 1) 120 120 120120 120 120 120 120 120 120 120 N,N-dimethyl-β-methoxypropionamide (note2) N,N-dimethyl-β-octoxypropionamide (note 3) Dibutyl ether (note 4)Propylene glycol monomethyl ether (note 5) Monomeric mixture monomerPLACCEL FM2D 30 30 30 30 25 30 10 (m-1) PLACCEL FM3 (note 6) 40 monomerLight Ester P-1M 10 30 25 30 (m-2) Phosmer PE (note 7) 40 Phosmer PP(note 8) 55 monomer 2-acrylamide-2- 28 (m-4) methylpropane- sulfonicacid monomer monomer (m-6-1) 40 40 (m-6) monomer (m-6-2) 35 monomer(m-6-3) 55 monomer (m-6-4) 40 monomer monomer (m-8-1) (m-8) styrene 3030 25 20 15 15 22 30 35 35 30 35 2-ethylhexyl acrylate 10 5 laurylmethacrylate 10 5 20 5 cyclohexyl methacrylate 30 10 10 5 10 10 5 10n-butyl acrylate 2-hydroxyethyl acrylate 5 5 10 15 15 15 15 t-butylperoxy-2-ethylhexanoate 6 6 6 6 6 6 3 6 6 6 6 6 Polymerization initiatordipropylene glycol dimethyl ether 30 solution N-methyl-2-pyrrolidone(note 1) 30 30 30 30 30 30 30 30 30 30 30 N,N-dimethyl-β-methoxypropio-namide (note 2) N,N-dimethyl-β-octoxypropio- namide (note 3) dibutylether (note 4) propylene glycol monomethyl ether (note 5) t-butylperoxy-2-ethylhexanoate 1 1 1 1 1 1 1 1 1 1 1 1 Solid concentration(mass %) 39 39 39 39 39 39 39 39 39 39 39 39 Acid value (mgKOH/g) 125125 105 125 119 130 72 98 98 98 100 102 Hydroxyl value (mgKOH/g) 45 4545 45 68 60 45 61 69 69 69 69 Number-average molecular weigh (×10⁴) 2 22 2 2 2 2 2 2 2 2 2 Example Comparative Example 13 14 15 16 17 18 19 1 23 4 Pigment-dispersing resin solution A-13 A-14 A-15 A-16 A-17 A-18 A-19A-20 A-21 A-22 A-23 Dipropylene glycol dimethyl ether 20N-methyl-2-pyrrolidone (note 1) 120 100 100 120 120 120 120N,N-dimethyl-β-methoxypropionamide (note 2) 20N,N-dimethyl-β-octoxypropionamide (note 3) 120 Dibutyl ether (note 4)120 Propylene glycol monomethyl ether (note 5) 120 120 Monomeric mixturemonomer PLACCEL FM2D 30 30 30 10 10 10 30 30 30 (m-1) PLACCEL FM3 (note6) 5 monomer Light Ester P-1M 30 30 6 30 30 15 (m-2) Phosmer PE (note 7)Phosmer PP (note 8) monomer 2-acrylamide-2- (m-4) methylpropane-sulfonic acid monomer monomer (m-6-1) 40 40 40 40 (m-6) monomer (m-6-2)monomer (m-6-3) monomer (m-6-4) monomer monomer (m-8-1) 57 (m-8) styrene23 30 30 40 7 30 25 20 25 2-ethylhexyl acrylate 23 30 10 10 10 laurylmethacrylate 9 5 5 30 cyclohexyl methacrylate 5 10 10 5 10 5 5 10n-butyl acrylate 40 2-hydroxyethyl acrylate 10 10 10 10 10 15 t-butylperoxy-2-ethylhexanoate 6 6 6 4 6 6 6 6 6 6 6 Polymerization initiatordipropylene glycol dimethyl ether 3 solution N-methyl-2-pyrrolidone 3027 27 30 30 30 30 N,N-dimethyl-β-methoxypropio- 3 namide (note 2)N,N-dimethyl-β-octoxypropio- 30 namide (note 3) dibutyl ether (note 4)30 propylene glycol monomethyl ether (note 5) 30 30 t-butylperoxy-2-ethylhexanoate 1 1 1 1 1 1 1 1 1 1 1 Solid concentration (mass%) 39 39 39 39 39 39 39 39 39 39 39 Acid value (mgKOH/g) 71 125 125 2598 98 98 125 125 63 98 Hydroxyl value (mgKOH/g) 52 45 45 90 61 61 61 4545 45 69 Number-average molecular weigh (×10⁴) 2 2 2 2 2 2 2 2 2 2 2(note 1) N-methyl-2-pyrrolidone: a solvent containing no hydroxyl groupand having a solubility in 20° C. water of at least 100 mass %, (note 2)N,N-dimethyl-β-methoxypropionamide: a solvent containing no hydroxylgroup and having a solubility in 20° C. water of at least 100 mass %,(note 3) N,N-dimethyl-β-octoxypropionamide: a solvent containing nohydroxyl group and having a solubility in 20° C. water less than 100mass %, (note 4) dibutyl ether: a solvent containing no hydroxyl groupand having a solubility in 20° C. water less than 100 mass %, (note 5)propylene glycol monomethyl ether: a solvent containing hydroxyl groupand having a solubility in 20° C. water of at least 100 mass %, (note 6)PLACCEL FM-3: tradename, Daicel Chemical Industries, Ltd., a monomerformed by adding 3 mols of ε-caprolactone per mol of 2-hydroxyethylmethacrylate, (note 7) Phosmer PE: tradename, Uni-Chemical Co., acidphospoxypolyoxyethylene glycol monomethacrylate, (note 8) Phosmer PP:tradename, Uni-Chemical Co., acid phosphoxypolyoxypropylene glycolmonomethacrylateProduction of Hydroxyl-containing Acrylic Resin (C1)

Production Example 6

A reactor equipped with a thermometer, thermostat, stirrer, refluxcondenser, nitrogen-inlet pipe and dropping device was charged with 130parts of deionized water and 0.52 part of AQUALON KH-10 (note 9) whichwere stirred and mixed in gaseous nitrogen current. The temperature wasraised to 80° C., and then 1% of the total amount of a later specifiedmonomeric emulsion (1) and 5.3 parts of 6% aqueous ammonium persulfatesolution were introduced into the reactor and kept at 80° C. for 15minutes. Then the remainder of the monomeric emulsion (1) was droppedinto the reactor which was maintained at the same temperature, over 3hours, followed by an hour's aging. Thereafter a monomeric emulsion (2)as specified later was added dropwise over an hour, aged for an hour,and the reaction mixture was cooled to 30° C. under gradual addition of40 parts of an aqueous 5% dimethylethanolamine solution into thereactor. The content was discharged while being filtered through Nyloncloth, mesh size of 100, to provide a water-dispersible,hydroxyl-containing acrylic resin (C1-1) having an average particle sizeof 100 nm [as measured with a submicron particle size distributionmeasuring device, COULTER N4 Model (tradename, Beckman Coulter, Inc.),as to a sample diluted with deionized water at 20° C.] and solidconcentration of 30%. Thus obtained hydroxyl-containing acrylic resinhad an acid value of 33 mgKOH/g and hydroxyl value of 25 mgKOH/g.

(Note 9) AQUALON KH-10: polyoxyethylene alkyl ether sulfate esterammonium salt: Daiichi Kogyo Seiyaku Co., Ltd., active ingredient=97%

Monomeric emulsion (1): a monomeric emulsion obtained by mixing andstirring 42 parts of deionized water, 0.72 part of AQUALON KH-10, 2.1part of methylenebisacrylamide, 2,8 parts of styrene, 16.1 parts ofmethyl methacrylate, 28 parts of ethyl acrylate and 21 parts of n-butylacrylate

Monomeric emulsion (2): a monomeric emulsion obtained by mixing andstirring 18 parts of deionized water, 0.31 part of AQUALON KH-10, 0.03part of ammonium persulfate, 3 parts of styrene, 5.1 parts of2-hydroxyethyl acrylate, 5.1 parts of methacrylic acid, 6 parts ofmethyl methacrylate, 1.8 parts of ethyl acrylate and 9 parts of n-butylacrylate.

Production Examples 7-10

Repeating the operations of Production Example 6 except that the blendsas shown in the following Table 2 were used, water-dispersible,hydroxyl-containing acrylic resins (C₁₋₂) to (C₁₋₅) were obtained.

Table 2 shows the starting composition (by parts), solid content (%),acid value (mgKOH/g) and hydroxyl value (mgKOH/g) of each of thewater-dispersible, hydroxyl-containing acrylic resins (C1-1) to (C1-5).

TABLE 2 Production Example 6 7 8 9 10 Hydroxyl-containing acrylic resinC1-1 C1-2 C1-3 C1-4 C1-5 Deionized water 130 130 130 130 130 AQUALONKH-10 0.52 0.52 0.52 0.52 0.52 6% Aqueous ammonium persulfate 5.3 5.35.3 5.3 5.3 Monomeric emulsion (1) deionized water 42 42 42 42 42AQUALON KH-10 0.72 0.72 0.72 0.72 0.72 methylenebisacrylamide 2.1 2.1allyl methacrylate 2.1 2.1 acrylamide 2.1 styrene 2.8 2.8 2.8 2.8 2.8methyl methacrylate 16.1 16.1 16.1 16.1 16.1 ethyl acrylate 28 28 28 2828 n-butyl acrylate 21 21 21 21 21 Monomeric emulsion (2) deionizedwater 18 18 18 18 18 AQUALON KH-10 0.31 0.31 0.31 0.31 0.31 ammoniumpersulfate 0.03 0.03 0.03 0.03 0.03 styrene 3 3 2-ethylhexyl acrylate 33 2-hydroxyethyl acrylate 5.1 5.1 5.1 5.1 5.1 methacrylic acid 5.1 5.15.1 5.1 5.1 methyl methacrylate 6 6 6 6 6 ethyl acrylate 1.8 1.8 1.8 1.81.8 n-butyl acrylate 9 9 9 9 9 5% Aqueous 2-(dimethylamino)ethanolsolution 40 40 40 40 40 Solid content (%) 30 30 30 30 30 Acid value(mgKOH/g) 33 33 33 33 33 Hydroxyl value (mgKOH/g) 25 25 25 25 25

In Table 2, methylenebisacrylamide and allyl methacrylate in themonomeric emulsion (1) are polymerizable unsaturated monomers (c-2)having 2 polymerizable unsaturated groups per molecule. Of these,methylenebisacrylamide is a polymerizable unsaturated monomer (c-2′)having at least 2 polymerizable unsaturated groups and at least 1 amidogroup per molecule. Also styrene and 2-ethylhexyl acrylate in themonomeric emulsion (2) are hydrophobic polymerizable unsaturatedmonomers (c-4).

In Table 2, among those water-dispersible, hydroxyl-containing acrylicresins (C1-1) through (C1-5), (C1-1) to (C1-3) correspond to core-shelltype water-dispersible acrylic resin(C1′).

Production of Hydroxyl-containing Polyester Resin (C2)

Production Example 11

A reactor equipped with a thermometer, thermostat, stirrer, refluxcondenser and water-separator was charged with 109 parts oftrimethylolpropane, 141 parts of 1,6-hexanediol, 126 parts ofhexahydrophthalic anhydride and 120 parts of adipic acid, and thetemperature therein was raised from 160° C. to 230° C. over 3 hours,followed by 4 hours' condensation reaction at 230° C. Then further 38.3parts of trimellitic anhydride was added to the resulting condensationreaction product to add carboxyl groups thereto, reacted at 170° C. for30 minutes and diluted with 2-ethyl-1-hexanol (whose soluble mass in 100g of 20° C. water: 0.1 g) to provide a hydroxyl-containing polyesterresin solution (C2-1) having a solid concentration of 70%. Thus obtainedhydroxyl-containing polyester resin had an acid value of 46 mgKOH/g,hydroxyl value of 150 mgKOH/g and weight-average molecular weight of6,400. In the starting composition, the total content of alicyclicpolybasic acid in the acid component was 46 mol %, based on the totalamount of the acid component.

Production Example 12

A reactor equipped with a thermometer, thermostat, stirrer, refluxcondenser and water-separator was charged with 111 parts oftrimethylolpropane, 143 parts of 1,6-hexanediol, 50 parts ofhexahydrophthalic anhydride, 100 parts of isophthalic acid and 106 partsof adipic acid, and the temperature therein was raised from 160° C. to230° C. over 3 hours, followed by 4 hours' condensation reaction at 230°C. Then further 38 parts of trimellitic anhydride was added to theresulting condensation reaction product to add carboxyl groups thereto,reacted at 170° C. for 30 minutes and diluted with 2-ethyl-1-hexanol(whose soluble mass in 100 g of 20° C. water: 0.1 g) to provide ahydroxyl-containing polyester resin solution (C₂₋₂) having a solidconcentration of 70%. Thus obtained hydroxyl-containing polyester resinhad an acid value of 46 mgKOH/g, hydroxyl value of 151 mgKOH/g andweight-average molecular weight of 6,100. In the starting composition,the total content of alicyclic polybasic acid in the acid component was17 mol %, based on the total amount of the acid component.

Production Example 13

Production Example 11 was repeated except that the diluting solvent,2-ethyl-1-hexanol, was replaced with ethylene glycol mono-n-butyl ether(whose soluble mass in 100 g of 20° C. water: unlimited), to provide apolyester resin solution (C2-3).

Production of Paint Composition

Example 20

In an agitation mixing vessel, 19 parts of aluminium pigment paste,GX-180A (tradename, Asahikasei Metals Co., Ltd., metal content 74%), 35parts of 2-ethyl-1-hexanol (whose soluble mass in 100 g of 20° C. water:0.1 g), 10 parts of the pigment-dispersing resin solution (A-1) asobtained in Example 1 and 0.2 part of 2-(dimethyl-amino)ethanol werehomogeneously mixed to provide a pigment dispersion.

Then 100 parts of the acrylic resin emulsion (C1-1) as obtained inProduction Example 6, 57 parts of the polyester resin solution (C2-1) asobtained in Production Example 11, 64 parts of above pigment dispersionand 37.5 parts of CYMEL 325 (tradename, Nippon Cytec Industries, Inc.,melamine resin, solid content 80%) were homogeneously mixed. Further apolyacrylic acid thickener (PRIMAL ASE-60, tradename, Rohm & Haas Co.),2-(dimethyl-amino) ethanol and deionized water were added to provide awater-based paint composition (X-1) having a pH 8.0; solid content 23%and the viscosity as measured with Ford cup No. 4 at 20° C. of 40seconds.

Examples 21-45 and Comparative Examples 5-8

Example 20 was repeated except that the composition of each blend waschanged to that as indicated in the following Table 3, to providewater-based paint compositions (X-2) through (X-26), and (X-28) through(X-31) having a pH 8.0, solid content 23% and viscosity of 40 seconds asmeasured with Ford cup No. 4 at 20° C.

Example 46

In an agitation mixing vessel, 19 parts of aluminium pigment paste,GX-180A (tradename, Asahikasei Metals Co., Ltd., metal content 74%), 35parts of 2-ethyl-1-hexanol (whose soluble mass in 100 g of 20° C. water:0.1 g), 10 parts of the pigment-dispersing resin solution (A-9) asobtained in Example 9 and 0.2 part of 2-(dimethyl-amino)ethanol werehomogeneously mixed to provide a pigment dispersion.

Then 100 parts of the acrylic resin emulsion (C1-1) as obtained inProduction Example 6, 57 parts of the polyester resin solution (C2-1)obtained in Production Example 11, 64 parts of above pigment dispersionand 37.5 parts of CYMEL 325 (tradename, Nippon Cytec Industries, Inc.,melamine resin, solid content 80%) were homogeneously mixed. Further aurethane association type thickener (UH-752, tradename, ADEKACorporation), 2-(dimethylamino)ethanol and deionized water were added toprovide a water-based paint composition (X-27) having a pH 8.0; solidcontent 23% and the viscosity as measured with Ford cup No. 4 at 20° C.of 40 seconds.

TABLE 3 Example 20 21 22 23 24 25 Paint Composition X1 X2 X3 X4 X5 X6Pigment Pigment-dispersing resin (A) Pigment-dispersing resin solution(A-1) 10 Dispersion Pigment-dispersing resin solution (A-2) 10Pigment-dispersing resin solution (A-3) 10 Pigment-dispersing resinsolution (A-4) 10 Pigment-dispersing resin solution (A-5) 10Pigment-dispersing resin solution (A-6) 10 Pigment-dispersing resinsolution (A-7) Pigment-dispersing resin solution (A-8)Pigment-dispersing resin solution (A-9) Pigment-dispersing resinsolution (A-10) Pigment-dispersing resin solution (A-11)Pigment-dispersing resin solution (A-12) Pigment-dispersing resinsolution (A-13) Pigment-dispersing resin solution (A-14)Pigment-dispersing resin solution (A-15) Pigment-dispersing resinsolution (A-16) Pigment-dispersing resin solution (A-17)Pigment-dispersing resin solution (A-18) Pigment-dispersing resinsolution (A-19) Pigment-dispersing resin solution (A-20)Pigment-dispersing resin solution (A-21) Pigment-dispersing resinsolution (A-22) Pigment-dispersing resin solution (A-23) Pigment (B)GX-180A 19 19 19 19 19 19 Hydrophobic solvent (E) 2-ethyl-1-hexanol 3535 35 35 35 35 ethylene glycol mono-n-butyl ether (note 10)2-(dimethylamino)ethanol 0.2 0.2 0.2 0.2 0.2 0.2 Hydroxyl-Hydroxyl-containing acrylic resin hydroxyl-containing acrylic resindispersion liquid (C1-1) 100 100 100 100 100 100 containing (C1)hydroxyl-containing acrylic resin dispersion liquid (C1-2) Resinhydroxyl-containing acrylic resin dispersion liquid (C1-3) (C)hydroxyl-containing acrylic resin dispersion liquid (C1-4)hydroxyl-containing acrylic resin dispersion liquid (C1-5)Hydroxyl-containing polyester hydroxyl-containing polyester resindispersion liquid (C2-1) 57 57 57 57 57 57 resin (C2)hydroxyl-containing polyester resin dispersion liquid (C2-2)hydroxyl-containing polyester resin dispersion liquid (C2-3) CuringMelamine resin (D1) CYMEL 325 37.5 37.5 37.5 37.5 37.5 37.5 agent (D)Blocked polyisocyanate compound BYHYDUR VPLS2310 (note 11) (D3) Example26 27 28 29 30 Paint Composition X7 X8 X9 X10 X11 PigmentPigment-dispersing resin (A) Pigment-dispersing resin solution (A-1)Dispersion Pigment-dispersing resin solution (A-2) Pigment-dispersingresin solution (A-3) Pigment-dispersing resin solution (A-4)Pigment-dispersing resin solution (A-5) Pigment-dispersing resinsolution (A-6) Pigment-dispersing resin solution (A-7) 10Pigment-dispersing resin solution (A-8) 10 Pigment-dispersing resinsolution (A-9) 10 Pigment-dispersing resin solution (A-10) 10Pigment-dispersing resin solution (A-11) 10 Pigment-dispersing resinsolution (A-12) Pigment-dispersing resin solution (A-13)Pigment-dispersing resin solution (A-14) Pigment-dispersing resinsolution (A-15) Pigment-dispersing resin solution (A-16)Pigment-dispersing resin solution (A-17) Pigment-dispersing resinsolution (A-18) Pigment-dispersing resin solution (A-19)Pigment-dispersing resin solution (A-20) Pigment-dispersing resinsolution (A-21) Pigment-dispersing resin solution (A-22)Pigment-dispersing resin solution (A-23) Pigment (B) GX-180A 19 19 19 1919 Hydrophobic solvent (E) 2-ethyl-1-hexanol 35 35 35 35 35 ethyleneglycol mono-n-butyl ether (note 10) 2-(dimethylamino)ethanol 0.2 0.2 0.20.2 0.2 Hydroxyl- Hydroxyl-containing acrylic resin hydroxyl-containingacrylic resin dispersion liquid (C1-1) 100 100 100 100 100 containingResin (C1) hydroxyl-containing acrylic resin dispersion liquid (C1-2)(C) hydroxyl-containing acrylic resin dispersion liquid (C1-3)hydroxyl-containing acrylic resin dispersion liquid (C1-4)hydroxyl-containing acrylic resin dispersion liquid (C1-5)Hydroxyl-containing polyester hydroxyl-containing polyester resindispersion liquid (C2-1) 57 57 57 57 57 resin (C2) hydroxyl-containingpolyester resin dispersion liquid (C2-2) hydroxyl-containing polyesterresin dispersion liquid (C2-3) Curing Melamine resin (D1) CYMEL 325 37.537.5 37.5 37.5 37.5 agent (D) Blocked polyisocyanate compound BYHYDURVPLS2310 (note 11) (D3) Example 31 32 33 34 35 Paint Composition X12 X13X14 X15 X16 Pigment Pigment-dispersing resin (A) Pigment-dispersingresin solution (A-1) Dispersion Pigment-dispersing resin solution (A-2)Pigment-dispersing resin solution (A-3) Pigment-dispersing resinsolution (A-4) Pigment-dispersing resin solution (A-5)Pigment-dispersing resin solution (A-6) Pigment-dispersing resinsolution (A-7) Pigment-dispersing resin solution (A-8)Pigment-dispersing resin solution (A-9) Pigment-dispersing resinsolution (A-10) Pigment-dispersing resin solution (A-11)Pigment-dispersing resin solution (A-12) 10 Pigment-dispersing resinsolution (A-13) 10 Pigment-dispersing resin solution (A-14) 10Pigment-dispersing resin solution (A-15) 10 Pigment-dispersing resinsolution (A-16) 10 Pigment-dispersing resin solution (A-17)Pigment-dispersing resin solution (A-18) Pigment-dispersing resinsolution (A-19) Pigment-dispersing resin solution (A-20)Pigment-dispersing resin solution (A-21) Pigment-dispersing resinsolution (A-22) Pigment-dispersing resin solution (A-23) Pigment (B)GX-180A 19 19 19 19 19 Hydrophobic solvent (E) 2-ethyl-1-hexanol 35 3535 35 35 ethylene glycol mono-n-butyl ether (note 10) 2-(dimethylamino)ethanol 0.2 0.2 0.2 0.2 0.2 Hydroxyl- Hydroxyl-containingacrylic resin hydroxyl-containing acrylic resin dispersion liquid (C1-1)100 100 100 100 100 containing Resin (C1) hydroxyl-containing acrylicresin dispersion liquid (C1-2) (C) hydroxyl-containing acrylic resindispersion liquid (C1-3) hydroxyl-containing acrylic resin dispersionliquid (C1-4) hydroxyl-containing acrylic resin dispersion liquid (C1-5)Hydroxyl-containing polyester hydroxyl-containing polyester resindispersion liquid (C2-1) 57 57 57 57 57 resin (C2) hydroxyl-containingpolyester resin dispersion liquid (C2-2) hydroxyl-containing polyesterresin dispersion liquid (C2-3) Curing Melamine resin (D1) CYMEL 325 37.537.5 37.5 37.5 37.5 agent (D) Blocked polyisocyanate compound BYHYDURVPLS2310 (note 11) (D3) Example 36 37 38 39 40 Paint Composition X17 X18X19 X20 X21 Pigment Pigment-dispersing resin (A) Pigment-dispersingresin solution (A-1) Dispersion Pigment-dispersing resin solution (A-2)Pigment-dispersing resin solution (A-3) Pigment-dispersing resinsolution (A-4) Pigment-dispersing resin solution (A-5)Pigment-dispersing resin solution (A-6) Pigment-dispersing resinsolution (A-7) Pigment-dispersing resin solution (A-8) 10 10Pigment-dispersing resin solution (A-9) Pigment-dispersing resinsolution (A-10) Pigment-dispersing resin solution (A-11)Pigment-dispersing resin solution (A-12) Pigment-dispersing resinsolution (A-13) Pigment-dispersing resin solution (A-14)Pigment-dispersing resin solution (A-15) Pigment-dispersing resinsolution (A-16) Pigment-dispersing resin solution (A-17) 10Pigment-dispersing resin solution (A-18) 10 Pigment-dispersing resinsolution (A-19) 10 Pigment-dispersing resin solution (A-20)Pigment-dispersing resin solution (A-21) Pigment-dispersing resinsolution (A-22) Pigment-dispersing resin solution (A-23) Pigment (B)GX-180A 19 19 19 19 19 Hydrophobic solvent (E) 2-ethyl-1-hexanol 35 3535 35 35 ethylene glycol mono-n-butyl ether (note 10) 2-(dimethylamino)ethanol 0.2 0.2 0.2 0.2 0.2 Hydroxyl- Hydroxyl-containingacrylic resin hydroxyl-containing acrylic resin dispersion liquid (C1-1)100 100 100 containing Resin (C1) hydroxyl-containing acrylic resindispersion liquid (C1-2) 100 (C) hydroxyl-containing acrylic resindispersion liquid (C1-3) 100 hydroxyl-containing acrylic resindispersion liquid (C1-4) hydroxyl-containing acrylic resin dispersionliquid (C1-5) Hydroxyl-containing polyester hydroxyl-containingpolyester resin dispersion liquid (C2-1) 57 57 57 57 57 resin (C2)hydroxyl-containing polyester resin dispersion liquid (C2-2)hydroxyl-containing polyester resin dispersion liquid (C2-3) CuringMelamine resin (D1) CYMEL 325 37.5 37.5 37.5 37.5 37.5 agent (D) Blockedpolyisocyanate compound BYHYDUR VPLS2310 (note 11) (D3) Example 41 42 4344 45 46 Paint Composition X22 X23 X24 X25 X26 X27 PigmentPigment-dispersing resin (A) Pigment-dispersing resin solution (A-1)Dispersion Pigment-dispersing resin solution (A-2) Pigment-dispersingresin solution (A-3) Pigment-dispersing resin solution (A-4)Pigment-dispersing resin solution (A-5) Pigment-dispersing resinsolution (A-6) Pigment-dispersing resin solution (A-7)Pigment-dispersing resin solution (A-8) 10 10 Pigment-dispersing resinsolution (A-9) 10 10 10 10 Pigment-dispersing resin solution (A-10)Pigment-dispersing resin solution (A-11) Pigment-dispersing resinsolution (A-12) Pigment-dispersing resin solution (A-13)Pigment-dispersing resin solution (A-14) Pigment-dispersing resinsolution (A-15) Pigment-dispersing resin solution (A-16)Pigment-dispersing resin solution (A-17) Pigment-dispersing resinsolution (A-18) Pigment-dispersing resin solution (A-19)Pigment-dispersing resin solution (A-20) Pigment-dispersing resinsolution (A-21) Pigment-dispersing resin solution (A-22)Pigment-dispersing resin solution (A-23) Pigment (B) GX-180A 19 19 19 1919 19 Hydrophobic solvent (E) 2-ethyl-1-hexanol 35 35 35 35 35 ethyleneglycol mono-n-butyl ether (note 10) 35 2- (dimethylamino)ethanol 0.2 0.20.2 0.2 0.2 0.2 Hydroxyl- Hydroxyl-containing acrylic resinhydroxyl-containing acrylic resin dispersion liquid (C1-1) 100 100 100100 containing (C1) hydroxyl-containing acrylic resin dispersion liquid(C1-2) Resin hydroxyl-containing acrylic resin dispersion liquid (C1-3)(C) hydroxyl-containing acrylic resin dispersion liquid (C1-4) 100hydroxyl-containing acrylic resin dispersion liquid (C1-5) 100Hydroxyl-containing polyester hydroxyl-containing polyester resindispersion liquid (C2-1) 57 57 57 57 resin (C2) hydroxyl-containingpolyester resin dispersion liquid (C2-2) 57 hydroxyl-containingpolyester resin dispersion liquid (C2-3) 57 Curing Melamine resin (D1)CYMEL 325 37.5 37.5 37.5 37.5 30 37.5 agent Blocked polyisocyanatecompound BYHYDUR VPLS2310 (note 11) 15 (D) (D3) Comparative Example 5 67 8 Paint Composition X28 X29 X30 X31 Pigment Pigment-dispersing resin(A) Pigment-dispersing resin solution (A-1) DispersionPigment-dispersing resin solution (A-2) Pigment-dispersing resinsolution (A-3) Pigment-dispersing resin solution (A-4)Pigment-dispersing resin solution (A-5) Pigment-dispersing resinsolution (A-6) Pigment-dispersing resin solution (A-7)Pigment-dispersing resin solution (A-8) Pigment-dispersing resinsolution (A-9) Pigment-dispersing resin solution (A-10)Pigment-dispersing resin solution (A-11) Pigment-dispersing resinsolution (A-12) Pigment-dispersing resin solution (A-13)Pigment-dispersing resin solution (A-14) Pigment-dispersing resinsolution (A-15) Pigment-dispersing resin solution (A-16)Pigment-dispersing resin solution (A-17) Pigment-dispersing resinsolution (A-18) Pigment-dispersing resin solution (A-19)Pigment-dispersing resin solution (A-20) 10 Pigment-dispersing resinsolution (A-21) 10 Pigment-dispersing resin solution (A-22) 10Pigment-dispersing resin solution (A-23) 10 Pigment (B) GX-180A 19 19 1919 Hydrophobic solvent (E) 2-ethyl-1-hexanol 35 35 35 35 ethylene glycolmono-n-butyl ether (note 10) 2- (dimethylamino)ethanol 0.2 0.2 0.2 0.2Hydroxyl- Hydroxyl-containing acrylic resin hydroxyl-containing acrylicresin dispersion liquid (C1-1) 100 100 100 100 containing (C1)hydroxyl-containing acrylic resin dispersion liquid (C1-2) Resinhydroxyl-containing acrylic resin dispersion liquid (C1-3) (C)hydroxyl-containing acrylic resin dispersion liquid (C1-4)hydroxyl-containing acrylic resin dispersion liquid (C1-5)Hydroxyl-containing polyester hydroxyl-containing polyester resindispersion liquid (C2-1) 57 57 57 57 resin (C2) hydroxyl-containingpolyester resin dispersion liquid (C2-2) hydroxyl-containing polyesterresin dispersion liquid (C2-3) Curing Melamine resin (D1) CYMEL 325 37.537.5 37.5 37.5 agent Blocked polyisocyanate compound BYHYDUR VPLS2310(note 11) (D) (D3) (note 10) ethylene glycol mono-n-butyl ether: itsmass soluble in 100 g of 20° C. water is unlimited, (note 11) BYHYDURVPLS2310: tradename, Sumika Bayer Urethane Co., Ltd., a blockedpolyisocyanate compound; solid content 38%.Coating Film-forming Method (Preparation of Test Panels)

Test panels of the respective water-based paint compositions(X-1)-(X-31) as obtained in above Examples 20-46 and ComparativeExamples 5-8 were prepared as follows, which were subjected to thefollowing evaluation tests.

(Preparation of Coated Objects for the Tests)

A zinc phosphate-treated cold-rolled steel sheet was electrocoated withELECRON GT-10 (tradename, Kansai Paint Co., a thermosetting epoxyresin-containing cationic electrocoating paint) to a dry film thicknessof 20 μm, which was cured by heating at 170° C. for 30 minutes. Onto theelectrocoated film, an intermediate paint, TP-65-2 (tradename, KansaiPaint Co., a polyester resin-amino resin organic solvent-basedintermediate paint) was applied to a dry film thickness of 35 μm, andcured by heating at 140° C. for 30 minutes, to provide the samplecoating object.

Example 47

Onto the above coating object, the water-based paint composition (X-1)as obtained in Example 1 was applied with a rotary atomizing typebell-formed electrostatic coater to a dry film thickness of 15 μm,allowed to stand for 2 minutes and then preheated at 80° C. for 3minutes. Then onto the uncured coated surface, MAGICRON KINO-1210(tradename, Kansai Paint Co., an acrylic resin-containing, organicsolvent-based top clear paint) was applied to a dry film thickness of 35μm and allowed to stand for 7 minutes, followed by heating at 140° C.for 30 minutes to cure the two coating films simultaneously to provide atest panel.

Examples 48-73 and Comparative Examples 9-12

Example 47 was repeated except that the water-based paint composition(X-1) in Example 47 was replaced with those shown in the following Table4, to provide the test panels of Examples 48-73 and Comparative Examples9-12.

Evaluation Test

The test panels as obtained in above Examples 47-73 and ComparativeExamples 9-12 were evaluated by the following test methods. The resultsof the evaluation were as shown in the following Table 4.

(Test Method)

Interlayer adherability: The multilayer coating film on each test panelwas crosscut with a cutter to the depth reaching the substrate, to formone-hundred 2 mm×2 mm squares. Then an adhesive cellophane tape wasstuck thereon, and rapidly peeled off at 20° C. Then remaining conditionof the crosscut coating film was examined and evaluated according to thefollowing standard.

: One-hundred squares of the coating film remained, and no minorchipping off in the coating film at the cut-in edges with the cutter wascaused.

O: One-hundred squares of the coating film remained but minor chippingoff in the coating film at the cut-in edges with the cutter wasobserved.

Δ: Remaining number of the squares was 90-99.

x: Remaining number of the square was not more than 89.

Water resistance: The test panels were immersed in 40° C. warm water for240 hours, withdrawn, dried at room temperature for 12 hours, and givena test similar to the above interlayer adherability test. The evaluationstandard also was identical.

Appearance: Coated surface of each test panel was given colorimetry witha multi-angle spectrophotometer, MA-68II (tradename, X-Rite Co.) to bemeasured of respective L* values at angles 15° and 110° from the regularreflection light of the light entered at an incident angle of 45°. Fromthe L* value at the light receiving angle of 15° and that at the lightreceiving angle of 110°, flip-flop value of the coating film wasdetermined according to the following equation:Flip-flop value=L* value at light receiving angle of 15°/L* value atlight receiving angle of 110°.

The greater the flip-flop value, the greater the variation in L* values(value) according to the observation angle (light receiving angle), andthe better the coating film appearance.

TABLE 4 Result of Evaluation Point Interlayer Water Compositionadherability resistance Appearance Example 47 X-1 ◯ ◯ 4.2 48 X-2

4.2 49 X-3

4.2 50 X-4

4.2 51 X-5

◯ 4.1 52 X-6

4.3 53 X-7 ◯ ◯ 4.0 54 X-8

4.4 55 X-9

4.4 56 X-10

4.3 57 X-11

◯ 4.3 58 X-12

◯ 4.2 59 X-13 ◯ ◯ 4.0 60 X-14

4.2 61 X-15

4.2 62 X-16

◯ 4.2 63 X-17

◯ 4.3 64 X-18

◯ 4.3 65 X-19 ◯ ◯ 4.3 66 X-20

4.3 67 X-21

4.2 68 X-22

◯ 4.1 69 X-23

◯ 4.1 70 X-24

4.3 71 X-25

4.2 72 X-26

4.4 73 X-27

4.5 Comparative 9 X-28 ◯ X 3.3 Example 10 X-29 ◯ X 3.2 11 X-30 ◯ Δ 3.512 X-31 ◯ X 3.4

The invention claimed is:
 1. A method for producing a pigment-dispersingresin (A) containing divalent group(s) represented by the followingformula (I):

(wherein R₁ is a C₁₋₁₀ alkylene group, m is an integer of 1-30, and them recurring units,

may be the same or different, phosphoric acid group(s) and/or sulfonicacid group(s), comprising: copolymerizing a polymerizable unsaturatedmonomeric mixture (a-3): a mixture of polymerizable unsaturatedmonomer(s) (m-6) having the divalent group represented by the aboveformula (I) and phosphoric acid group, and polymerizable unsaturatedmonomer(s) (m-7) other than the polymerizable unsaturated monomer(s)(m-6), wherein the polymerizable unsaturated monomeric mixture (a-3) iscomposed of 1-90 mass % of the polymerizable unsaturated monomer(s)(m-6), and 10-99 mass % of the polymerizable unsaturated monomer(s)(m-7), based on a total amount of the polymerizable unsaturated monomers(m-6) and (m-7); in a reaction solvent (b) which comprises at least 30mass %, based on a total mass of the reaction solvent, of an organicsolvent (b-1) having no hydroxyl group and having a solubility in 20° C.water of at least 100 mass %.
 2. The method according to claim 1, inwhich the organic solvent (b-1) is selected from the group consisting ofether solvents, amide solvents and urea solvents.
 3. The methodaccording to claim 2, in which the reaction solvent (b) contains 50-100mass %, based on the total mass of the reaction solvent (b), of theorganic solvent (b-1).
 4. The method according to claim 1, in which themonomeric mixture is copolymerized by solution polymerization method. 5.The method according to claim 1, in which the pigment-dispersing resin(A) contains the divalent group(s) represented by the formula (I) withina range of 1-70 mass %, based on a mass of the pigment-dispersing resin(A).
 6. The method according to claim 1, in which the pigment-dispersingresin (A) has an acid value within a range of 30-200 mgKOH/g.
 7. Apigment-dispersing resin (A) which is prepared by the method accordingto claim
 1. 8. A pigment dispersion comprising a pigment-dispersingresin (A) which is prepared by the method according to claim 1 andpigment (B).
 9. A water-based paint composition comprising the pigmentdispersion according to claim 8, hydroxyl-containing resin (C) andcuring agent (D).
 10. The water-based paint composition according toclaim 9, which comprises, per 100 mass parts of a combined solid resincontent of the hydroxyl-containing resin (C) and curing agent (D),0.5-30 mass parts of the pigment-dispersing resin (A), 2-70 mass partsof pigment (B), 40-90 mass parts of hydroxyl-containing resin (C) and10-60 mass parts of curing agent (D).
 11. An article coated with thewater-based paint composition according to claim
 9. 12. A multilayercoating film-forming method which comprises applying onto a coatingobject the water-based paint composition according to claim 9, applyingonto the resulting uncured coating film a clear paint, and heating tocure the two coating films simultaneously.
 13. An article coated by themultilayer coating film-forming method according to claim 12.